Cyperaceae

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Cyperaceae

Description

Annual or perennial, often grass-like herbs, only the monotypic African genus Microdracoides tree-like; Leaves often 3- ranked, more rarely distichous or polystichous, basal and/or cauline, usually sheathing at the base, the sheaths closed (in Mal.), very rarely open, the blades as a rule sessile, linear (grass-like) or setaceous, rarely lanceolate and petioled, rarely much reduced or even absent; Inflorescence paniculate, anthelate, capitate, or spicate, with few to many spikelets, rarely reduced to a single spikelet, often subtended by 1-several leafy involucral bracts. Flowers simple, inconspicuous, each subtended by a bract (glume), arranged in small spiciform units (spikelets), in subfam. Caricoideae strictly unisexual, in subfam. Cyperoideae tribe Hypolytreae composed of monandrous lateral ‘flowers’ and a terminal ovary, in tribe Cypereae reduced to bisexual synanthia, a few of which may be functionally male or female by abortion of the other sex. Stamens often 3, not rarely reduced to 2 or 1, very rarely more than 3 to numerous; Ovary solitary, superior, usually 2- or 3-carpellate, unilocular; Fruit indehiscent, a nut (often termed achene), sessile, or seated on a disk, free, or surrounded by a modified prophyll (perigynium, utricle). Seed erect, with thin testa not adhering to the pericarp;

Distribution

Africa: present, Seychelles (Seychellespresent) African region: present Asia-Tropical:, Borneo (Sabahpresent); New Guineapresent; Philippines (Philippinespresent) Australian-centred, extending with a single species through Malesia to Asia: present Madagascar: present Mt Kinabalu: present Old World: present Pacific: present Solomons: present Tropics and subtropics: present ancient high mountains of North Sumatra: present extra-tropical and in the tropics almost confined to montane stations: present extra-tropical zones: present northern hemisphere: present temperate zones: present tropical lowlands and hills: present warm and temperate zones: present west Pacific: present worldwide: present
About 70-80 genera with probably some 4000 spp., throughout the world.
Among the genera occurring in Malesia only Capitularina is endemic (in New Guinea and the Solomons) and Paramapania (throughout Malesia) is almost endemic, with one Mal. sp. extending to the West Pacific.
Malesian Cyperaceous genera show geographical relations in several directions: some have marginally westwards extending areas, for example Oreobolus, which genus is largely distributed in the southern half of the Pacific, reaching its most western station on the ancient high mountains of North Sumatra. . Another example is the very similarly distributed genus Uncinia of which the most western stations are found on Mt Kinabalu in North Borneo and in the Philippines.
Another type of marginal occurrence is that of Kobresia (incl. Schoenoxiphium), a genus which is distributed over Africa and the northern hemisphere and shows up with one species in the ancient high mountains of North Sumatra.
Several genera possess a worldwide range, sometimes restricted to the tropics and subtropics, e.g. Bulbostylis, Fuirena, Hypolytrum, Lipocarpha, and Mapania, sometimes however distributed over the warm and temperate zones, e.g. Carex, Cladium, Cyperus, Eleocharis, Fimbristylis, Machaerina, Rhynchospora, Schoenus, Scirpus, and Scleria. Among the latter Machaerina and Scleria have only a few representatives in the extra-tropical zones; reversely Carex is largely extra-tropical and in the tropics almost confined to montane stations. Cyperus and Fimbristylis occur predominantly in the tropical lowlands and hills, and rapidly diminish in number towards the temperate zones.
The following genera are confined to the Old World: Carpha, Costularia, and Tetraria; Lepironia has a similar range, but its African stations are restricted to Madagascar, while Thoracostachyum occurs in the African region only in the Seychelles.
Finally a number of genera occur only in the Old World, but are absent from Africa, viz Gahnia (), Scirpodendron, Lepidosperma (), and Tricostularia, among which the latter two are properly Australian-centred, extending with a single species through Malesia to Asia.
Distribution of species. A fairly large number of species occurring in Malesia have (i) a worldwide or almost worldwide distribution, most of them in the warmer regions of the globe; for example:
  • Bulbostylis barbata
  • Carex curta
  • Carex echinata
  • Carex pseudocyperus
  • Carex remota
  • Cladium mariscus
  • Cyperus brevifolius
  • Cyperus compressus
  • Cyperus cuspidatus
  • Cyperus cyperoides
  • Cyperus digitatus
  • Cyperus halpan
  • Cyperus kyllingia
  • Cyperus odoratus
  • Cyperus pedunculatus
  • Cyperus polystachyos
  • Cyperus sesquiflorus
  • Cyperus unioloides
  • Eleocharis geniculata
  • Eleocharis nigrescens
  • Eleocharis parvula (not Australia)
  • Eleocharis retroflexa
  • Fimbristylis complanata
  • Fimbristylis cymosa
  • Fimbristylis dichotoma
  • Fimbristylis ferruginea
  • Fimbristylis hispidula
  • Fimbristylis littoralis
  • Fimbristylis squarrosa
  • Rhynchospora corymbosa
  • Rhynchospora gracillima (not America)
  • Rhynchospora triflora (not Australia)
  • Scleria lithosperma

It is not unexpected that these species are almost all plants which are indifferent to soil and belong to open lowland habitats, often inhabiting places with little competition, such as beaches and waste land, and are suitable to pioneering in disturbed and cultivated places. It is striking that there are no forest dwellers among them. It is not impossible that some may have attained their large area due to man in pre-historic or post-Columbian time. They are also almost all very common species.

This is not always the case, as there are also some widely distributed species which show remarkable (ii) disjunct areas, e.g. Eleocharis variegata (Africa, Madagascar, Mauritius, then in North Sumatra and twice found in New Guinea), Car ex michauxiana (NE. North America, China, Japan, and the highlands of New Guinea), Scleria mikawana (Africa, Ceylon, Japan, and in New Guinea), Scleria annularis (India to China, then New Guinea), and Scleria parvula (from Ceylon to Korea, then Luzon and New Guinea).

Possibly future collections will fill the gaps, as many collectors have neglected to collect sedges.

A range like that of Scleria parvula may show a quite natural pattern, as there are in New Guinea several plant species ranging from Japan, via Formosa and the Philippines to that island, although such cases mostly refer to mountain plants, e.g. several Carices.

A few seemingly rather queer ranges have appeared to be due to misidentification or to curiously mis-localized collections for which is referred to Cyperus esculentus, Carex divuls, and Car ex muricata(= C.pairaei).

Besides the two categories mentioned, worldwide and disjunct, there are four others, three of which show ranges extending from the borders just into Malesia, viz from Asia, Australia, and from the Pacific, whilst the fourth category concerns the endemic species of Malesia.

Of each of these groups examples will be given, not an exhaustive enumeration.
  • (iii) Asian representatives (mountain plants marked by an asterisk):
    • Carex *duriuscula (Korea, New Guinea)
    • Carex *michquxiana (northern hemisphere, New Guinea)
    • Cyperus substramineus (Asia, Malaya)
    • Eleocharis *acicularis (northern hemisphere, N. Sumatra, N. Luzon)
    • Eleocharis *attenuata (Japan, China, New Guinea)
    • Fimbristylis adenolepis (Thailand, Indo-China, Kangean Is.)
    • Fimbristylis *disticha (Burma to China, N. Sumatra)
    • Fimbristylis *pierotii (Himalaya to Japan, Luzon)
    • Fimbristylis *thomsonii (Himalaya to Formosa, Malaya, N. Sumatra, Palawan)
    • Machaerina *maingayi (Tonkin, Malaya)
    • Rhynchospora malasica (Japan, China to W. Malesia)
    • Scirpus wallichii (Japan to India, Malaya, Philippines)
    • Scirpus *wichurai (Himalaya, N. Sumatra)
    • Scleria neesii (SE. Asia, Malaya)
    • Scleria reticulata (SE. Asia, Malaya)
    • Scleria thwaitesiana (Ceylon to Thailand, Malaya)
  • (iv) Australian species just entering the borders of Malesia (mountain plants marked by an asterisk):
    • Carpha *alpina (New Zealand, Tasmania, Australia, New Guinea)
    • Cyperus angustatus (Australia, New Guinea)
    • Cyperus aquatilis (ditto)
    • Cyperus dietrichiae (Australia, New Britain)
    • Cyperus fulvus (Australia, New Guinea)
    • Cyperus *lucidus (ditto)
    • Cyperus pedunculosus (ditto)
    • Eleocharis *acuta (New Zealand, Tasmania, Australia, New Guinea)
    • Eleocharis *sphacelata (ditto)
    • Fimbristylis furva (Australia; New Guinea: Wassi Kussa, Merauke; Aru Is.)
    • Fimbristylis recta (Australia; S. New Guinea: Wassi Kussa)
    • Fimbristylis schultzii (Australia, Bali, Sumba)
    • Machaerina *gunnii (Australia, New Guinea)
    • Machaerina *teretifolia (New Zealand, Australia, W. New Guinea)
    • Oreobolus *pumilio (Tasmania, Australia, New Guinea)
    • Schoenus *melanostachys (Australia, Mindoro, Mt Kinabalu)
    • Schoenus *nitens (S. Chile, New Zealand, Australia, New Guinea)
    • Schoenus sparteus (Australia, New Guinea, Wetar)
    • Scirpus *aucklandicus (New Zealand, Australia, New Guinea)
    • Scirpus *crassiusculus (ditto)
    • Scirpus *inundatus (temperate South America, New Zealand, Australia, New Guinea)
    • Scirpus *subtilissimus (New Zealand, Australia, New Guinea, W to Luzon, Mt Kinabalu)
    • Scleria brownii (Australia, New Caledonia, Tonga, New Guinea)
    • Scleria novae-hollandiae (Australia, Micronesia, New Guinea, Luzon)
    • Scleria tricuspidata (Australia, S. Moluccas: Aru Is.)
  • (v) The Pacific is botanically much poorer and has therefore only few species extending into East Malesia:
    • Machaerina mariscoides (Polynesia, New Guinea)
    • Scleria polycarpa (Fiji, Melanesia, New Guinea, Moluccas). .
  • (vi) Of many genera endemic species occur in Malesia amongst which are many forest dwelling species of the Mapanieae (mountain plants marked with an asterisk):
    • Capitularina involucrata (New Guinea)
    • Carex *eremostachya (New Guinea & Solomons)
    • Carex *gajonum (N. Sumatra)
    • Carex *loheri (Philippines)
    • Carex malaccensis (Malaya)
    • Carex *merrillii (Philippines)
    • Carex nodiflora (Philippines)
    • Carex palawanensis (Philippines)
    • Carex *sarawaketensis (New Guinea)
    • Carex spathaceo-bracteata (New Guinea)
    • Costularia pilisepala (Borneo, New Guinea)
    • Cyperus cinereobrunneus (New Guinea)
    • Cyperus meistostylis (New Guinea)
    • Cyperus neoguineensis (New Guinea)
    • Cyperus pachycephalus (New Guinea)
    • Cyperus subpapuanus (New Guinea)
    • Eleocharis *brevicollis (New Guinea)
    • Eleocharis sundaica (Alor)
    • Fimbristylis blepharolepis (New Guinea)
    • Fimbristylis caesia (Philippines, Java)
    • Fimbristylis calcicola (Malaya)
    • Fimbristylis capilliculmis (New Guinea)
    • Fimbristylis celebica (Central Celebes)
    • Fimbristylis lineatisquama (Philippines)
    • Fimbristylis macassarensis (Luzon, SW. Celebes, Madurai I.)
    • Fimbristylis malayana (Malaya)
    • Fimbristylis subdura (Java)
    • Fimbristylis sumbaensis (Sumba I.)
    • Fimbristylis wetarensis (Wetar I.)
    • Hypolytrum capitulatum (Borneo)
    • Hypolytrum humile (West Java)
    • Kobresia *kobresioidea (N. Sumatra)
    • Machaerina aspericaulis (Mt Kinabalu)
    • Machaerina *lamii (New Guinea)
    • Mapania angustifolia (Borneo)
    • Mapania debilis (Borneo)
    • Mapania foxworthyi (Borneo)
    • Mapania graminea (Borneo)
    • Mapania holttumii (Malaya)
    • Mapania latifolia (Borneo)
    • Mapania longiflora (Borneo, Malaya)
    • Mapania lorea (W. Malesia)
    • Mapania maschalina (Borneo)
    • Mapania micropandanus (Malaya)
    • Mapania monostachya (Borneo)
    • Mapania sessilis (W. Malesia)
    • Mapania spadicea (Borneo)
    • Mapania squamata (W. Malesia)
    • Mapania wallichii (W. Malesia)
    • Oreobolus *kukenthalii (N. Sumatra, Malaya)
    • Paramapania flaccida (New Guinea)
    • Paramapania gracillima (Philippines)
    • Paramapania longirostris (New Guinea)
    • Paramapania radicans (Borneo)
    • Paramapania rostrata (Philippines)
    • Paramapania simplex (New Guinea)
    • Schoenus *curvulus (New Guinea to Mt Kinabalu)
    • Schoenus delicatulus (Palawan, Mt Kinabalu)
    • Schoenus *longibracteatus (New Guinea, Mt Kinabalu)
    • Scirpus *beccarii (Sumatra)
    • Scirpus *junghuhnii (N. Sumatra)
    • Scleria cyathophora (W. Malesia)
    • Scleria densispicata (Luzon)
    • Scleria papuana (New Guinea)
    • Scleria pygmaeopsis (Sumba)
    • Tetraria borneensis (Borneo)

Dispersal

Local extension byvegetativegrowth and even propagation is a very common fea- ture in Cyperaceae, on account of the frequent occurrence of rhizomes, runners and more rarely bulbs. This leads frequently to local almost pure stands (colonies), so characteristic of many swamp and highland species, and also to their rapid extension on waste land. It is characteristic in most sedges of the sandy beach, e.g. in Cyperus bulbosus, C. pedunculatus (), C. stoloniferus (), etc. It is of course equally common among inland species, e.g. in Cyperus rotundus (), C. brevifolius (), and other species ofCyperus sect. Kyllingia. This is one of the reasons that some sedges are difficult to eradicate, notably Cyperus rotundus, as parts of rhizomes or bulbs are in this way dispersed and act as vegetative diaspores.

As in most large families there is quite an array of dispersal devices of the fruits.

Unfortunately the number of actual observations in Malesia is very small and examples are largely derived from the northern hemisphere. They have also to be judged from the structure of the nuts and the habitat of the plants. Experiments in this field are also badly needed, as it is of course insufficient to find stomachs full of sedge nuts without checking latent germination power in those found in dung or droppings.

Fruits (nuts) of Cyperaceae are generally small to minute, except those of Scirpodendron, a marsh plant, in which they measure 1-1½ by 1 cm (). Mostly they have no device adapted to a special- ized kind of dispersal, but some have, for dispersal by water, by animals, by the sea, and a few by wind. Also vegetative dispersal can take place, by rhizomes or tubers. Vegetative dispersal by stolons is for example almost predominant in the very common Cyperus rotundus which very seldom sets fruit.

Most data in this paragraph are taken from RIDLEY’S informative compilation ().

Sea-water. Some sedges which are characteristic of the sandy beach are certainly seaborne. These are Cyperus bulbosus, C. dubius, C. hyalinus, C.pedunculatus (Remirea) (), C. radians, C. stoloniferus () and furthermore Fimbristylis cymosa and F. sericea. One might conclude that they would all be common species, like C.pedunculatus. They occupy indeed generally wide ranges, but although beaches abound in the archipelago, they are far from common, e.g. Cyperus bulbosus. For their scarcity one can assume either that some are selective for beach microniches or that there is some deficiency with their dispersal capacity. Such questions ask for experimental evidence. The most widespread is Cyperus pedunculatus and this has a specialized floating mechanism, a swollen corky rachilla internode enveloping the nut.

Aquatic dispersal. As so many sedges inhabit marshy soil or swamps, stream- and river-banks, and man-made ricefields, where they often occur in great quantity, fresh water must be a most important vector. Some of these marsh plants possess certain devices. Of some Car ex species it is known that they derive buoyancy power by means of the inflated utricle enveloping the nut; Cyperus odoratus has swollen corky rachilla internodes remaining attached to the nut as in Cyperus pedunculatus; Cyperus cephalotes () has a corky pericarp for buoyancy; nuts of Cyperus platy sty lis with narrow corky edges also float as found by CLARKE (); Scirpodendron () has large fruits with a stony endocarp surrounded by a thick corky layer keeping them afloat for a long time; in Cladium mariscus the pericarp contains air-cells with thin walls and wide intercellular spaces and has been observed to float for 15 months; also Scirpus maritimus owes floating power to the pericarp structure.

However, calculated in percentages the number of species possessing floating power are in distinct minority: normally nuts of Cyperus, Eleocharis, Scirpus, etc. sink in water. It is remarkable how few species have buoyant nuts, yet to observe how widespread and common, sometimes dominant, they occur in swampy places, even though the local dominance is not seldom due to vegetative reproduction, e.g. by stolons in the perennial species.

This discrepancy can in part be explained by arguing that even sinking seeds are of course dispersed by running water and floods and furthermore that whole plants or their debris are found in river drift. Cyperus cephalotes () is even a characteristic drifting plant, as described by COERT (), as is Cyperus platystylis. Also vast numbers of non-buoyant nuts are found in drift and 'sudd', some having a means of attaching themselves, by their perianth bristles; even tubers of a Cyperus species have been found in such drift. Also in rice-fields nuts may be dispersed from one terrace to an other by irrigation methods.

Though this accidental dispersal must be very common, it cannot well serve to explain dispersal of the majority of species and specimens found in swamps, permanent or temporary, which are not connected by streams or rivers. For this it is assumed that the major vector is the birds.

Dispersal by birds. Examination of stomach contents of birds has revealed that especially ducks can really feed on sedge nuts. In one stomach 30.000 nuts were found of a Cyperus, in an other 64.000 of an Eleocharis, and in stomachs and crops also nuts were found of Carex, Cladium, Fimbristylis, Rhynchospora, Scirpus, Scleria, etc. Although, as remarked before, it has insufficiently been checked how far this food is digested, it can be assumed that some nuts will retain germination power and are dispersed with the excreta, a sort of accidental endozoic dispersal.

In very few cases the nuts are attractive to birds by a display of contrasting colours, e.g. in Gahnia, where the nuts are yellow, or scarlet, and contrast vividly with the dark-brown to black inflorescences out of which they dangle from the filaments. In Sumatra this has been observed by JACOBSON with Pycnonotus bimaculatus. The nuts are very hard and whether they are digested is not clear.

Carex baccans has fleshy red-coloured utricles which are equally attractive to birds.

Epizoic dispersal by birds is assumed to be more important, as many sedges have very small seed which may adhere, with mud, to feet, beak and feathers of wading birds. In Europe this has been observed (KERNER) or supposed for species of Carex, Cyperus, Eleocharis, Rhynchospora, Scirpus, and Cladium mariscus.

It may well be that bristles of certain species of Scirpus are favourable for epizoic dispersal. A specialized organ which certainly serves for this purpose is found in Uncinia, in which the rachilla protrudes from the utricle and is provided at the apex with a remarkable hook by which the utricles are adhesive to fur or feathers.

To which distances dispersal is effected by epizoic dispersal can of course not be observed, but in Europe it is assumed to cover several dozens of miles in e.g. Scirpus maritimus, in order to explain isolated localities in inland saline habitats through dispersal by wild-fowl. In East Java several halophilous sedges are found near salt (mud)wells which may be accounted for in this way. However, it remains quite uncertain whether accidental epizoic dispersal may also lead to effective longdistance dispersal, for example, to explain the total range of Scirpus maritimus, which occurs on the northern hemisphere and in Australia, but is extremely rare in Malesia, being a few times collected only in Luzon (in the mountains, but also at low altitude) and in New Guinea (in the high mountains). For, if long-distance transtropical dispersal is assumed to explain these huge disjunctions, shortdistance dispersal in the same area must occur infinitely more frequently and this species should then not be so extremely rare in Malesia; this reasoning throws a grave doubt on the assumption of long- distance dispersal.

Though in Uncinia effective epizoic dispersal can not be doubted, here also is doubt about its being effective over long distances (1000 km or more). Though on the one hand the range of Uncinia is, not reckoned oceanic disjunctions, fairly coherent and ‘natural’, it matches on the other hand that of many other plants which have quite different ways of dispersal or none (like Nothofagus). So a word of warning is in place against too hasty explanations based on the effectiveness of the specialized function of hooked fruits.

Cattle is also assumed to contribute to dispersal of seed of sedges as has been observed in Europe (Carex, Scirpus). Nuts of Fimbristylis globulosa and F. littoralis do not yield to digestion of water buffaloes. This serves only for short distances and anyway such nuts are also dispersed in rice-field areas by water.

Ants play a minor role in short-distance dispersal of sedges; ant dispersal has been observed in Car ex in Europe where in some species the base of the utricule is provided with a sort of appendage with an oily body (SERNANDER).

The role of man is certainly large but difficult to evaluate in extent and illustrate by examples. Traffic, transport, road-building, etc. must have contributed to dispersal of nuts and rhizomes, also sometimes overseas as for example Cyperus sphacelatus and C. aromaticus. In northern Italy several tropical and subtropical aquatic and marsh plant species are found in rice-fields of which the seed is assumed to have been carried as contamination of the rice seed supply.

In Italy there is also the remarkable unique locality of Cyperus polystachyos in the isle of Ischia near Naples near the solfatara and hotwells as reported already by G. VON MARTENS (), where it can maintain itself by the grace of local, permanent higher temperature. This occurrence can only be accounted for by accidental dispersal by man from Asia Minor or Egypt, maybe dating back to surviving Crusaders who on return took to this famous holiday resort.

A similar occurrence of Cyperaceae outside their natural area was observed by VAN STEENIS, who found Cyperus halpan, a common rice-field plant ascending to some 1650 m, on the summit of Mt Agung (Bali) at c. 3000 m near fumaroles together with a dozen other lowland or hill species. It is assumed that the diaspores of these plants were accidentally dispersed by man during the annual pilgrimage to the summit of this mountain where they can grow and maintain themselves in the subalpine permanent ‘open air hothouses’ near the fumaroles. Likewise R. VAN DER VEEN collected Cyperus cyperinus near hotwells in Lombok on Mt Rindjani at 2000 m, a species ascending normally to c. 1300 m.

Wind plays a minor role in dispersal of seeds in the tropics, but it is assumed for the Australasian highland Carpha alpina in the Papuan Alps which possesses a plumose, persistent perianth of some 9 mm length. Here again longdistance dispersal is merely an assumption, because it immediately induces the question why then the genus Eriophorum which is so widely distributed over the northern hemisphere and occurs also in continental tropical-montane SE. Asia has not been capable to invade the West Malesian highlands.

Wind has also incidentally been mentioned for Scirpus in which it has been observed that the glume may occasionally remain attached to the nut, acting as a wing. A similar mechanism has been men- tioned for certain Gahnia species where the lengthening stamens tear the nut loose and remain sometimes entangled around it, but the nuts in Gahnia are heavy and are readily detached. For the various interesting mechanisms loosening the nut in this genus I refer to the discussion under the genus.

Morphology

For a long time taxonomists have tried in Cyperaceae to derive the unisexual flower from the bisexual one, viz that of Caricoideae from that of Cyperoideae, but there remained always an unbridgeable gap between these two types, as in the unisexual flowers there is never a vestige of a perianth nor of the other sex.

If the opposite course is pursued, however, and we start our reasoning from the unisexual flower this gap can well be bridged. This idea was developed by MATTFELD () and independently by HOLTTUM (). It was further developed by me ().

Like in many other families the primitive structures are found in the tropical representatives. Instead of assessing insight in structure starting from a temperate species of Scirpus, we take Scirpodendron, a very coarse tropical sedge, with broad cutting leaves, large dense inflorescences, and drupaceous fruits attaining a centimetre in size. From the ground-plan of its spikelets with unisexual flowers the other types can easily be derived by (sometimes excessive) reduction, as is illustrated here by a number of diagrams in . Starting from the primitive type of Scirpodendron, the other types (Mapania, Paramapania, etc.) can easily be derived, until we arrive at Hypolytrum, in which in the partial inflorescence (spikelet) there are no scales between stamens and ovary, the spikelet thus becoming indistinguishable from the diagram of the ‘flowers’ of some Scirpus species. This leads to the view that the ‘flower’ of Cyperoideae, which was so neatly supposed by CLARKE and others to represent a characteristic pentacyclic diagram as is usual in many Monocotyledonous families, though with reductions in the whorls, is really a pseudanthium or synanthium.

An other most important feature is the interpretation of the structure of the spikelet and the role of the prophyll. In Cyperaceae as a rule the first leaf of every lateral branch is a 2-keeled prophyll, backing the axis from which the branch arises.

KUNTH () definitely showed that the utricle in Car ex, up till then generally taken for a perianth, is homologous with the prophyll, the margins of which are connate up to the top and so has become a bottle-shaped organ enclosing a female flower (later the nut). In Kobresia, as well as in the European genus Elyna and in the African genus Schoenoxiphium — which I all regard as congeneric (see my discussion in ) — the situation is more primitive than it is in Carex. The prophyll in these genera is either open or more or less connate at the margins, whereas the axis (rachilla) on which it is seated often bears some male flowers. In Car ex these male flowers have disappeared and only in a few species a reduced rachilla is still present. In Uncinia the vestige of the rachilla is at its apex transformed into a peculiar recurved hook which can be accepted to be homologous with an empty bract or reduced male flower; this hook is designated as a specialisation for epizoic dispersal. The idea of NELMES () that the unispicate Carices from Europe and North America with a vestigial rachilla belong to the genealogy of Uncinia is untenable.

According to the interpretation given above the morphological derivation of the structure of the spikelet and the essential role in it by the prophyll leads to the assumption that the most primitive state, with unisexual flowers, is still represented in the Mapanieae. Starting from the situation in Scirpodendron one can observe that in this tribe the prophyll (consisting of two transverse scales, which may be connate, in Hypolytrum sometimes even on both sides and thereby becoming more or less utriculiform) and flowers can be arranged in a series of successive reduction (vestigial to completely absent), leading finally in Cyperoideae to excessive reduction and the origin of pseudanthia. Another line of excessive reduction has led to the structure as is found in Caricoideae in which, however, the unisexuality of the flowers has been conserved.

PAX () suggested that there would be a basic difference in Cyperaceae, advancing that the structure of the spikelets in Cyperoideae is monopodial and in tribe Rhynchosporeae sympodial. On this account ASCHERSON & GRAEBNER () raised the latter tribe to subfamily rank. This is, however, fallacious: the structure of the spikelets is in all Cyperaceae probably sympodial (KERN, 1962, l.c.).

In passing it may be remarked that some genera were assigned to Rhynchosporeae by erroneous interpretation, e.g. Remirea which is simply a Cyperus in which a rachilla internode is transformed into a corky organ serving buoyancy (see the fuller account under the species). On the other hand Oreobolus is distinctly allied to Rhynchosporeae and must be placed in the Schoenoid affinity.

Embryography. Interesting data on the embryography were published by P. VAN DER VEKEN (), who examined the embryo in 342 spp. of Cyperoideae. He found 6 main types which he named the Cyperus, Carex, Schoenus, Fimbristylis, Bulbostylis, and Scirpus types. Some of these are depicted in .

It has appeared that in homogeneous taxa, e.g. in. Cyperus sens, lat., always the same embryo type is found. This is also true for e.g. Schoenus, Bulbostylis, Eleocharis, and Fuirena, on the generic level. In our opinion a type may also be characteristic on infra-generic level, e.g. in Fimbristylis, where sect. Abildgaardia and Actinoschoenus have embryotypes which differ from that in Fimbristylis. ln Scirpus there are not less than 7 different embryo types. Conversely, one embryo type may occur in more than one genus, e.g. Lipocarpha has the Cyperus type of embryo. Whereas the homogeneity of Cyperus is supported by embryography, one may conclude that Scirpus is distinctly heterogeneous. This might be an argument for systematic heterogeneity involving a possibly polyphyletic assemblage; each of the natural sections in Scirpus possesses namely according to VAN DER VEKEN (1964, p. 140) only one embryo type.

Though Scirpus confervoides (Websteria) has its own embryo type, similar to that of Eleocharis but somewhat more differentiated, I have kept it in Scirpus for flower-morphological reasons. As to Actinoschoenus, which has the Carex type of embryo combined with a Eucyperoid leaf-anatomy I have kept this in Fimbristylis, though VAN DER VEKEN (1964, p. 166) suggests it to belong to Rhynchosporeae (see rjk 591 under Fimbristylis thouarsii).

Anatomy

.

METCALFE (1971, l.c.) provided a comprehensive survey of anatomical structures occurring within the family. His reference book also contains a very full bibliography and summaries by GREGORY of anatomical data collected in the past. Most of the following is taken from this book.

Anatomical characters to be used for diagnostic purposes or for discussions of affinities are the following.

Shape of lamina in transverse section taken midway the apex and the sheathing base. In the generally occurring dorsiventral leaf type the lamina may be V-shaped (with flanged, medianly grooved and thick subtypes), corrugate, crescentiform (thin or thick), inversely W-shaped or triangular. The shapes of isobilateral leaves (Lepidosperma, Machaerina) range from subcruciform, winged fusiform, tetragonal, elliptical to constricted elliptical in transverse section. The pseudodorsiventral leaf type (restricted to Cladium) is V-shaped. Cylindrical leaves with a circular to subcircular shape of the transverse section occur in some species of Lipocarpha and Machaerina. METCALFE (1969, 1971) has suggested a derivation of the cylindrical, isobilateral and pseudodorsiventral leaf types from the dorsiventral ‘basic’ type.

Prickle hairs are very common in the family and of little taxonomic interest. Other hair types are more infrequent and have some diagnostic value. They include adpressed hairs with tips directed towards the leaf apex (some spp. of Costularia, Scirpus and Scleria), unicellular flexible hairs (some spp. of Carex, Fimbristylis, Fuirena, Rhynchospora, Schoenus and Scleria), unicellular long and stiff hairs (some spp. Of Carex, Fuirena, Rhynchospora and Schoenus), unicellular short and stiff hairs (some spp. of Carex, Fuirena, Gahnia, Lipocarpha, Oreobolus and Scleria) and finally lobed hairs in Schoenus (S. apogon). Papillae are present in a number of genera. In some species of Carex, Cladium, Fimbristylis, Lepidosperma, Lepironia, Machaerina and Scleria the papillae are restricted to the cells around the stomata and overarch the latter.

Epidermis. Stomata are generally paracytic but tend to be tetracytic in some genera. Silica bodies are of almost universal occurrence in the leaf epidermis of Cyperaceae and have proved to be of great taxonomic importance. They are absent or very doubtfully present in an unusual form in Hypolytrum and Lepironia, finely particulate silica has been noted in some species of Costularia, Fuirena, Oreobolus, Paramapania and Scleria. The bodies may be dome-shaped with their bases resting in the sinuations of anticlinal walls in Oreobolus or be present as solitary cones at the apices of sinuations of anticlinal walls (some spp. of Costularia and Scleria); cubical bodies associated with other types of silica bodies occur in Paramapania and Rhynchospora; warty spherical to hemispherical bodies in Capitularina and Scleria; bridge-shaped bodies in Mapania and Thoracostachyum; wedge-shaped in Scirpodendron and Thoracostachyum. The most common type is the conical type with its base resting on the inner periclinal wall. This type intergrades with the nodular one. These types occur in the majority of genera and may be present in different numbers per cell, the number and arrangement of the bodies being of diagnostic value. The epidermis may include bulliform cells.

In a number of Cyperaceae a parenchymatous or partly or wholly sclerenchymatous hypodermis is present. The presence or absence of bulliform cells and of a hypodermis is of restricted taxonomic value. Variations have been recorded below the species level. The distribution of sclerenchyma, mainly accompanying the vascular bundles shows an enormous range of variation within the family and the shapes of sclerenchyma girders, caps or strands may be of considerable diagnostic value at the species level.

The mesophyll of the leaves may be virtually homogeneous, differentiated in palissade and spongy chlorenchyma or may contain radiate chlorenchyma (that is radiating from the vascular bundles). The latter type is conspicuously represented in most or all species oiBulbostylis, Cyperus, Fimbristylis and Lipocarpha, some or all species of Fimbristylis, Fuirena, Hypolytrum and Rhynchospora show this feature less markedly. Air cavities or areas with translucent cells, which give rise to such cavities occur in a great number of genera.

The vascular bundles of the leaf are collateral and in most genera arranged in a single row as seen in transverse section. In cylindrical, isobilateral, pseudodorsiventral and a few dorsiventral leaves the arrangement differs. In cylindrical and isobilateral leaves they are arranged along the whole periphery of the transverse section. In the isobilateral leaves of Lepidosperma and Machaerina and the pseudodorsiventral leaves of Cladium they occur in opposite pairs with the xylem poles facing each other. This situation should not be confused with the arrangement of vascular bundles in two ranks in some dorsiventral leaves, each vascular bundle having a normal xylem and phloem arrangement. This occurs in species of Costularia, Cyperus, Lipocarpha, Mapania, Rhynchospora, Scirpodendron and Thoracostachyum. The vascular bundles are usually surrounded by a two-layered bundle sheath, with or without adaxial and/or abaxial merging with the accompanying sclerenchyma. Three basic types occur in Cyperaceae: 1) inner sheath sclerenchymatous, outer sheath parenchymatous (most common), 2) inner sheath parenchymatous, outer sheath sclerenchymatous (some species of Cyperus, Lipocarpha), and 3) bundle sheath three-layered, outer and inner sheath parenchymatous, middle layer sclerenchymatous (spp. of Bulbostylis, Carpha, Fimbristylis and Mapania). Some species show intermediate types of bundle sheaths.

Culm anatomy also provides useful diagnostic features. These also include outline in transverse section (triangular, circular, hemicircular, quadrangular, pentagonal, hexagonal, polygonal, trapezoid, winged fusiform, scutiform crescentiform and irregular), presence or absence and distribution of air cavities, arrangement of vascular bundles, and sclerenchyma.

Roots and rhizomes are less well known anatomically, and the characters thought to be of diagnostic value need further testing.

Relationships with other families. Gramineae are different from Cyperaceae mainly in epidermal structure. In Gramineae the silica bodies are morphologically entirely different and the epidermal cells are clearly differentiated in short and long cells. The latter feature, however, tends to be present in a few Cyperaceae as well. METCALFE (1971) has suggested that any phylogenetic relationship between the two families must be very remote. Restionaceae differ from most Cyperaceae in their culm anatomy. In Restionaceae there is a characteristic sequence of tissues: epidermis, chlorenchyma, parenchyma sheath, sclerenchyma sheath (enclosing peripheral vascular bundles) and medullary vascular bundles embedded in central parenchymatous ground tissue. In Cyperaceae some genera also possess a sclerenchyma ring in the culm, but the very regular zonation of tissues as in Restionaceae is always absent so that the resemblance of those Cyperaceae to Restionaceae remains superficial. Silica deposits occurring in some Restionaceae are either spheroidal nodular or are present as silica sand. Conical bodies, so characteristic of the majority of Cyperaceae are absent. Nodular bodies occur in a number of Cyperaceous genera but intergrade here with the conical type. According to METCALFE (1971) Cyperaceae are anatomically more similar to Juncaceae than to any other plant group. Juncaceae do not possess silica bodies, but this is also true for several genera of Cyperaceae. It may be noted in passing that most of the Cyperaceae lacking silica are amongst the genera belonging to the tribe Hypolytreae. This tribe is generally regarded as primitive within the family. It seems therefore justified to suggest that the plant group ancestral to Cyperaceae and Juncaceae also lacked silica bodies. The affinities of Cyperaceae with Juncaceae are also supported from other sources of evidence (cf. METCALFE, 1971, pp. 42 & 43).

Anatomical affinities within the family. It is impossible to define the tribes and subfamilies anatomically. All tribes contain such a range of anatomical variation and the overlap with other tribes is so extensive that only vague suggestions can be made. The tribe Hypolytreae exhibits a great range of variation. The unusual bridge- and wedge-shaped silica bodies of some genera only occur outside this tribe in a few genera of the Rhynchosporeae. The absence of distinct silica bodies is moreover more or less confined to genera belonging to Hypolytreae. Several genera, notably Chrysithrix and Chorizandra, show many resemblances with members of Rhynchosporeae (cf. BAAS, l.c., and METCALFE, 1971, l.c.). All other tribes typically contain some sort of conical silica bodies, and Capitularina of the Hypolytreae has also been recorded to contain this type. In my opinion this genus is rather remote from the other Hypolytreae on other anatomical grounds as well (BAAS, l.c.). The tribe Cypereae does not exhibit any striking anatomical features which make them stand out within Cyperaceae. Anatomically there are no objections against including genera usually treated in the separate tribe Scirpeae in Cypereae. Rhynchosporeae vary considerably in their anatomy. Yet Oreobolus is rather isolated anatomically. Some genera resemble Hypolytreae (see above). The tendency in some non-Malesian genera to have wedge-shaped silica bodies also points to an affinity between the two tribes. Sclerieae usually possess silica bodies of deviating types in addition to the common conical ones. This seems to be the only outstanding anatomical character within the tribe. Cariceae are quite homogeneous anatomically. Most of the characters shared by the genera constituting this tribe are, however, also of widespread occurrence throughout the other tribes. Vegetative anatomy does not provide supporting evidence to distinguish two subfamilies Cyperoideae and Caricoideae. — P. BAAS.

Uses

The following data are very concise and mostly taken from HEYNE (). See for more details in the text under the species.

Various sedges are used for plaiting mats and thatching, the most commonly used being Cyperus malaccensis, Eleocharis dulcis, Lepironia, Scirpodendron, Scirpus grossus, S. lacustris, S. litoralis, S. mucronatus, and Thoracostachyum sumatranum. The stems of Eleocharis sphacelatus are in New Guinea used to make rush skirts for women.

A peculiar use is made by fishermen of Cyperus malaccensis in Java (see the taxon and ).

The tubers of Eleocharis dulcis are edible and this species is sometimes cultivated for this purpose; possibly Malays brought it to the Northern Territory together with Egyptian Lotus.

The apex of the stem and the leaf-bases of the sprouts of Gahnia javanica have a most agreeable sweet taste of nuts, but serve only as a titbit to the wandering naturalist. In Papua the rhizomes of Machaerina articulata are eaten. In north Central Java (near Pemalang) stem-pieces of Cyperus malaccensis are thickly inserted in ropes which are used to catch fry of the bandeng fish ().

Noxious weeds are Cyperus rotundus etc. which by their subterranean tubers or rhizomes are difficult to eradicate.

Several Cyperaceae occurring in great quantity in marshes and swamps invade the wet rice-fields. Most common paddy field sedges are Cyperus difformis, C. halpan, C. iria, Fimbristylis littoralis and Scirpus juncoides. They are of course weeded out, but when the rice is harvested there are still many which escaped weeding and are abundantly fruiting.

As in many places the rice harvest is alternated with a dry farming crop, the seed (nuts) of the Cyperaceae must remain dormant in the soil because during the dry farming a quite different weed flora comes up.

Such areas have hence a ‘double weed flora’, and consequently the seed or fruit of the dryland farming weeds must also be dormant during the wet period of the growing of rice.

This is an interesting feature not yet fully disclosed, because we would like to know what factors are responsible for the dormancy of both categories, the secret of the factors inhibiting their germination.

Notes

This revision will be published in two instalments due to the fact that the treatment of Carex and Uncinia is not yet finished.

Phytochemo

The chemical characters of this huge family were summarized 10 years ago (). Accumulation of silicic acid, which is deposited in highly characteristic, anatomically easily demonstrable (spodograms) patterns, usual absence of oxalate of lime, the relatively frequent occurrence of flavonoid (i.e. condensed) tannins probably derived from leucoanthocyanins or protoanthocyanidins and preponderance of starch as a carbohydrate reserve seem to be typical of Cyperaceous plants. Some taxa produce essential oils which are deposited in more or less elongated oil cells. Cyanogenic compounds, alkaloids and saponins seem to occur exceptionally only in this family. The scantiness of known chemical facts was stressed in 1963. In the meantime phytochemical research has not totally neglected Cyperaceae. Much new information about alkaloids, flavonoids, quinones and phenolic ketones of roots and rhizomes, and about the chemical composition of essential oils of several species of Cyperus became available in recent time. The alkaloids of Carex brevicollis, harman, brevicollin and brevicarin, were shown by Russian authors to be all β-carboline-type bases. Alkaloids were reported for several other Cyperaceae; their structures, however, have still to be established. The essential oils of rootstocks of Cyperus articulatus, C. rotundus and C. scariosus were studied intensively by several groups of workers; sesquiterpenes and sesquiterpenic alcohols and ketones are their main constituents. The taxonomically probably most interesting developments, however, concern polyphenolic compounds. E. C. BATE-SMITH published his survey of leaf phenolics of monocotyledonous plants (). He noted a strong resemblance between Gramineae and Caricoideae and a tendency for Cyperoideae (Scirpoideae) to be “much more regular or ‘primitive’ in their phenolic pattern”; his sampling, however, was very poor with regard to Cyperaceae. H. T.CLIFFORD and J. B. HARBORNE () studied the flavonoid pigments of inflorescences of sedges and arrived at the conclusions that grasses and sedges are radically different and that in wind-pollinated plants the correlation between flavonoid chemistry and taxonomy breaks down. The common anthocyanidins, flavonols and flavones seemed to be lacking in sedges; 3-deoxyanthocyanidins (carexidin), aurones (aureusidin), chalcones (okanin) and leuco-anthocyanidins were shown to occur in Cyperaceae, but to be erratically distributed in the family. Later HARBORNE () studied leaf pigments of 62 species representing 11 genera. This time a rather close resemblance between grasses and sedges and additionally palms was noted. Glycoflavones and the flavones luteolin and tricin are widespread in leaves of sedges and flavonols including rutin were found only in Eriophorum latifolium, Fuirena pubescens and in 7 of the 44 species of Carex investigated. The predominant occurrence of flavonols in Carex flava and related species suggests, according to HARBORNE, that these are the more primitive taxa within the genus. Evidently much more facts about the chemistry and distribution of phenolic compounds are needed before sound taxonomic conclusions become possible.

Investigations aiming at extension of our knowledge were started by I. KUKKONEN (); many phenolics were demonstrated by him to occur in sedges; before a true evaluation of facts becomes possible, identification of these compounds is necessary.

However, for the study of species aggregates chromatographic comparisons of leaf phenolics may be valuable without identification of the compounds concerned (). Totally new compounds were detected in rootstocks of Australian Cyperaceae by R. J. ALLAN et al. (). These are the cyperaquinones and phenolic ketones, both probably derived from isoprenylated and acylated phloroglucinols. The cyperaquinones were found to occur in species of Cyperus, Fimbristylis, and in Cyperuspedunculatus (R.BR.) KERN (Remirea maritima L.). Only the last mentioned species was investigated accurately for phenolic ketones; remirol, remiridiol, preemirol and isoevodionol occur in its rootstocks. These phloroglucinol-derived new constituents of sedges seem to be promising for the study of infra- and intergeneric relationships, but less so for the study of relationships between families.

Summarizing it may be stated that even to-day our phytochemical knowledge of Cyperaceae is scanty. The facts available at present indicate that grasses and sedges share several striking features. Therefore the phytochemical data do not contradict the hypothesis postulating a common origin for these two large families of wind-pollinated Monocotyledons. - R. HEGNAUER.