Balanophoraceae

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Balanophoraceae

Description

Herbaceous, fleshy root parasites, destitute of chlorophyll and roots with yellowish white to yellow, brown, orange to red or rose pink colours. Inflorescence spadix-like with unisexual flowers ♂, ♀ or ♀♂, in the Mal. spp. unbranched.

Distribution

Africa: present Asia: present Asia-Tropical:, New Guineapresent Madagascar: present New Caledonia: present New Zealand: present South America: present tropical Africa to Tahiti and Marquesas: present tropics and subtropics of the world: present
About 45 species in 18 genera in the tropics and subtropics of the world. As to our present knowledge 7 genera are exclusively South American, 4 genera are exclusively African 2 are Asian, 1 is from Madagascar, 1 from New Zealand, and 1 from New Caledonia. Two genera have remarkable distributions, viz Langsdorffia with 3 species, 1 in South America, 1 in Madagascar and 1 in New Guinea, and Balanophora with 15 species from tropical Africa to Tahiti and Marquesas, one of the species covering almost the entire area (see B. abbreviata).

Pollination

Again very few observations have been reported. Various insects have been observed visiting male flowers of Balanophora fungosa subsp. indica (HANSEN). In Balanophora papuana the male flowers open in being touched (FORMAN). Inflorescences of Balanophora reflexa smell from fox in the morning (CORNER) and could possibly thus attract Diptera or Hymenoptera.
VAN STEENIS () observed that the supporting hairs of the female flowers in Rhopalocnemis excreted nectar, but no insect visitors were observed by him or VAN DER PIJL. GOVINDAPA & SHIVAMURTHY () found bees collecting pollen of Balanophora abbreviata and its ♀ flowers producing a sugary liquid.

Dispersal

Factual information is very scarce. RIDLEY () observed in Christmas I’and P. Aur in Johore that ‘in preserving specimens’ (of the monoecious B. abbreviata)’ the minute fruits drifted away on the high breezes, like the pollen of a conifer. They were produced in great abundance on the little plant and borne on short stalks The plants, which were very scanty grew in open wood or between high rocks.’ He also observed that this species is widely distributed in Oceanic islands, occurring, occurring from Madagascar and the Comores as far east as the Marquesas Is.
Diaspores are indeed very light: the average weight of those of B. fungosa subsp. indica are, 0.007 mg, that is only four times heavier than the lightest orchid seed.
However, RIDLEY correctly pointed out that ‘the other species grow in dense forest in wet spots their fruits are not so small and are apparently diffused mainly by rain-wash These are quite absent from other islands.’ This is not quite true; they do occur in islands, not only in those of the Malesian archipelago but B. fungosa subsp. fungosa occurs also in the Solomons, New Caledonia New Hebrides, and Fiji, while B. wilderi is confined to Rarotonga and Rapa Is.
For these others, and the species of the genera Rhopalocnemis, Exorhopala, and Lanssdorffin which all grow in the depth of dense everwet rain-forest, dispersal by wind is excluded while dispersal by rain-wash can only be very local and is insufficient to explain the large to almost world-wide ranges of Rhophalocnemis affinity and Langsdorffia respectively. They grow on the forest floor and often do emerge only very little from the litter. Their spadices decay gradually and rot away, as was observed in Rhopalocnemis ()
It has been advanced by KONINGSBERGER () that in the Javanese mountain forest pigs feed on tubers of Balanophora, but this appears obviously to be a loose assumption or a misinterpretation of their digging activity, as DOCTERS VAN LEEUWEN with his immense experience and acute observation denied it ().
VAN STEENIS () has advanced that dispersal of these forest floor parasites takes place, similarly as in Rafflesiaceae, epizoically by game, mainly by ungulates but possibly also by other animals, large and small.
The dioecism which prevails in several species, makes dispersal over long distances still more problematic similarly as in Rafflesiaceae in which species and genera show large, or even immense disjunctions. It is clear that these disjunct ranges are testimony of the great age of these parasite families and that the range histories reflect extinction and a chequered history going back to a dim past.
About the life-span of viable seed nothing is known unfortunately. Also about theway of infectingw the host plant and its first life-stages no factual data are available. In Rafflesia it has been experimentally that infection can only take place on wounded roots or stems. This may be ture for these Balano-phoraceae The solving of the secret of Balanophoraceous infection is one of the many ogals of future tropical research.

Morphology

In several species seed setting is by apogamy or parthenogenesis, as has been studied in Java or based on Javanese material by TREUB in Balanophora elongata (), LOTSY in B. fungosa subsp. indica var. globosa () and ERNST (). The same has been found in Rhopalocnemis by LOTSY () and ERNST ().
FAGERLIND () made it clear, however, that these authors were mostly wrong in their interpretation and concluded that normal sexual reproduction occurs in most Balanophoraceae. Within the genus Balanophora agamospermy was found only in B. fungosa subsp. indica var. globosa and in B. japonica.
FAGERLIND’S papers have shed doubt on the use of the terms ‘ovary cell’, ‘ovule’ and 'pendulous' nature of the latter, as there seems to be no cavity in the ovary. I have consequently abandoned these terms and restricted myself to speak of an embryo consisting of a few cells which is embedded in the tissue of the ovary.
VON GUTTENBERG () studied the anatomy of Balanophora material he collected in Sumatra and came to the conclusion that the tubers of Balanophora should be interpreted as root tubers. It should be realized, however, that the tuber contains also fused root tissue of the host. Compare .
A detailed, comprehensive review of the knowledge concerning the anatomy οf Balanophora is given by FAGERLIND (), where also important original observations are reported. HARMS () has summarized the knowledge concerning Balanophora as well as of other genera. Further METCALFE & CHALK () should be consulted and my thesis on Balanophora (). FAGERLIND has in a series of papers: , reviewed and given much new evidence concerning floral morphology and anatomy of several genera. The latest review by ΚUIJT () deals with most aspects of the biology of Balanophoraceae.

Taxonomy

In his masterly monograph () HOOKER f. treated 12 genera, as delimited today, and 28 species. treated as two families, viz Balanophoraceae and Langsdorffiaceae, what is now known as subfam. Balanophoroideae; he enumerated 51 species. In my recent revision of Balanophora () I reduced the number of species to 15. In Langsdorffia there seem to be 3 and in Thonningia only 1 species, which makes a total of 19 species today within subfam. Balanophoroideae.

Cytology

Because of their small size countings are very difficult in Balanophora. I have surveyed data and added some myself () in which n numbers are found to be c. 16 or c. 18, and 2n c. 36 for Balanophora abbreviata, 56 and 94-112 for B. japonica. DARLINGTON & WYLIE (1955) listed for Cynomorium n = 12 and for Helosis and Thonningia both n = 18.

Uses

Balanophora elongata contains large amounts of wax in the tubers and has been used on Java for making torches. Outside the Malesian area there are reports from Thailand and Japan on making bird-lime from the wax of Balanophora tubers.

Notes

Good material of Rhopalocnemis and Exorhopala is extremely scarce and it has been necessary to some extent to rely upon observations published by botanists, who studied fresh material (JUNGHUHN, VAN STEENIS, RIDLEY). Regarding Langsdorffia papuana nothing can be added to the careful observations made by GEESINK.

Phytochemo

Candles are prepared from species of Balanophora and Langsdorffia; their tissues contain large amounts of a wax-like substance called balanophorin. Balanophorin from Balanophora fungosa subsp. indica var. globosa (JUNGH.) HANSEN (err. B. ‘bulbosa’ JUNGH.) and B. elongata Bl. consists mainly of β-amyrin palmitate which is accompanied by small amounts of rubber. B. japonica MAKINO is used to prepare a bird-lime; it contains esters of β-amyrin and taraxasterol and probably appreciable amounts of rubber too. Several observations as well as some medicinal uses indicate that Balanophoraceae are rich in phenolic and tannin-like substances. Recent investigations with two species shed some light on the nature of these constituents. Large amounts of coniferin were isolated from a Balanophora species used in Thai medicine as an antiasthmatic; at the same time 0.3 % of β-amyrin palmitate was obtained (). From rhizomes of Lophophyturn leandri EICHL. WEINGES et al. isolated polymeric proanthocyanins (= condensed tannins), eriodictyol (a flavanon), taxifolin (a flavanonol), (-)-epicatechin and glycosides of eriodictyol, naringenin, quercetin and epicatechin (). These recent observations confirm the presence of condensed tannins and their building stones (catechins) in the family. However, trihydroxylated constituents (myricetin, gallic acid, gallo-catechins) were not yet detected in Balanophoraceae. Chemical knowledge of the taxon is still too scanty for a balanced chemosystematic evaluation. The patterns of phenolic and triterpenic constituents seem to agree rather well with the often accepted santalalean relationships (see ). It should be remembered, however, that most species have not yet been investigated hitherto and that fatty acids with acetylene linkages seem to be lacking in the family (: Balanophora fungosa FORST.). For additional references see: . — R. HEGNAUER.