Ficus L. subg. Sycidium (Miq.) Mildbr. & Burret sect. Sycidium Miq.
Content
Description
Trees or shrubs, terrestrial, commonly with intermittent growth;
hairs often with a swollen base and the longer brown ones often clustered.
internal hairs mostly present (abundant to few), less frequently absent;
Leaves spirally arranged, (sub)opposite (or subverticillate) or distichous, asymmetric to symmetric, often scabrous by rigid hairs or cystolith hairs;
stipules semi-amplexicaul to lateral, less commonly fully amplexicaul.
Fruits achenes, smooth, weakly tuberculate or finely punctate, mostly ± distinctly keeled or drupelets with tuberculate endocarp bodies (pyrenes).
Distribution
Asia-Tropical, from Samoa and Australia to Taiwan, Japan, and S China westwards to Réunion, Madagascar, and Africa (westwards to Senegal) present
The section comprises c. 80 species and ranges from Samoa and Australia to Taiwan, Japan, and S China westwards to Réunion, Madagascar, and Africa (westwards to Senegal); in Malesia 42 species.
Taxonomy
This section is distinct from sect. Palaeomorphe in the absence of adventitious roots, intermittent growth, hollow or solid but much pith containing leafy twigs, the arrangement of leaves spirally, (sub)opposite or subverticillate, absence of unilaterally decurrent base of the lamina, waxy glands at both sides of the midrib, and always small pistillodes in the staminate flowers.
Several groups of evidently or presumably related species can be recognized, but none with clear demarcations. The five (practical and informal) groups of species which can be distinguished are:
The coherence of the three groups circumscribed above indicates that they may constitute a natural entity centred in the eastern part of the range of distribution of the subsection, in contrast to the following groups.
A. Corner, E.J.H. 1960: Taxonomic notes on Ficus Linn., Asia and Australasia. IV. Subgen. Ficus sect. Sycidium. – Gard. Bull. Singapore 17, B. Corner, E.J.H. 1965: Check-list of Ficus in Asia and Australasia with keys to identification. – Gard. Bull. Singapore 21
- a. Ficus conocephalifolia-group (largely ser. Phaeopilosae Corner (1960)). — This group shows more or less clearly the features of intermittent growth as listed above. The group is characterized by stiff, bristle-like, often dark brown to almost black hairs. On the twigs, petioles and lamina, these hairs are not evenly distributed, but occur more or less clustered. The brown setose hairs are also found on the fig receptacle and have there a slightly swollen base, from which the hairs easily break off and then become irritant. In F. gul, these characteristic hairs can be (partly) replaced by whitish ones as is common in the F. copiosa-group. Relatively large lenticels occur just below the (scars of the) stipules. The leaves are spirally arranged. They vary from large to small, the large ones having longer petioles (up to 1/2 the length of the lamina) and also showing stronger differences in length of the petiole on the same twig than those with small leaves. The figs are axillary, ramiflorous, cauliflorous, or even flagelliflorous (in F. badiopurpurea). The receptacles vary from large to small, all are provided with lateral bracts, in some species (F. complexa and F. eustaphana) large ones. The ostiole is surrounded by a rosette of apical bracts, usually pointing upwards. The glabrous tepals are red, free or slightly so, or in F. badiopurpurea distinctly connate. The fruits are smooth and weakly to distinctly keeled. The group appears to be a natural one and comprises at least seven species: F. badiopurpurea, F. complexa, F. conocephalifolia, F. eustephana, F. gul, F. phaeosyce, and F. porphyrochaete. The group is centred in eastern New Guinea. Ficus complexa is also found in the western part of the island. Ficus gul is the only widespread species, extending to the Solomon Islands and westwards to the Philippines, Borneo, and the Lesser Sunda Islands. Most species are components of lowland forest, two species of montane forest. Several traits, as the presence of large leaves, relatively large figs, large stipules, and large lateral bracts on the fig receptacle appear to indicate that this group is the most primitive one in the subgenus. Moreover, because of the dark brown indumentum, members of this group have been linked up (or confused) with sect. ‘Bosscheria’ and with members of the F. pachyrrhachis-group in sect. Sycocarpus. These similarities might be an indication of a phylogenetic link.
Similarities in growth features and transitions from one type of indumentum into another suggest that this group is rather closely related to the F. copiosa-group. Ficus riedelii, endemic to Celebes and with some doubt included in the F. ulmifolia-group, shows in the tendency towards spirally arrangement of the leaves and features of the figs, as conspicuous lateral bracts, a rosette of bracts around the ostiole, and irritating hairs, also affinities to the F. conocephalifolia-group. - b. Ficus copiosa-group (largely ser. Copiosae Corner (1960)). — This group is largely similar to the F. conocephalifolia-group in the arrangement of the leaves and to some extent also in the variation in the length of the petioles, but the indumentum is often whitish, the rosette of bracts around the ostiole often absent, and the lateral bracts on the receptacle are small or absent. Moreover, the conspicuous lenticels on the leafy twigs below the stipules are lacking. Ficus opposita and F. cumingii, species with the short-petioled leaves predominantly (sub)opposite, but also alternate (distichous or in lax spirals) or sometimes even subverticillate, can be linked to the F. copiosa-group through F. wassa. The group thus comprises eight species: F. balica, F. copiosa, F. cumingii, F. floresana, F. heteropoda, F. opposita, F. primaria, F. sciaphila, and F. wassa. This group is western Malesian; F. copiosa and F. opposita extends to N Australia and the latter occurs disjunctly on an islet in the Sunda Strait.
- c. Ficus ulmifolia-group (largely ser. Scabrae Miq.; Corner 1960). — This group comprises species with (usually) distichous leaves with the petioles relatively short and about equal in length on the same leafy twigs. The occasional presence of subopposite leaves (in F. ulmifolia) and the tendency towards spirally arranged leaves (in F. riedelii and F. tonsa) indicate links to the F. copiosa-group. The lamina varies considerably in shape and dimensions, and the indumentum from whitish to brownish. Ficus leptodictya, F. tenuicuspidata, and F. tonsa are (largely) glabrous. The figs are often 1-1.5 cm diam., with or without conspicuous lateral bracts. The variation in the flowers is about the same as in the previous group. This group comprises in addition to the 18 species found in the Malesian region c. 20 occurring in the Pacific islands and in Australia, and possibly the Asian mainland species F. henryi and F. subincisa (see above), broadening the diversity of the group as a whole. The 19 Malesian species are: F. ampelas, F. elmeri, F. erinobotrya, F. fiskei, F. goniophylla, F. leptodictya, F. macrorrhyncha, F. melinocarpa, F. myiopotamica, F. odorata, F. pseudowassa, F. quercetorum, F. riedelii, F. schumanniana, F. stellaris, F. tenuicuspidata, F. tonsa, F. trachypison, and F. ulmifolia. The uncertain position of F. riedelii is mentioned under the first group of the section. The species of this group are elements of the eastern part of the Malesian region, four of these species extend to the Solomon Islands, and two of them, F. ampelas and F. melinocarpa, to Sumatra.
The coherence of the three groups circumscribed above indicates that they may constitute a natural entity centred in the eastern part of the range of distribution of the subsection, in contrast to the following groups.
- d. Ficus montana-group (including subsect. Varinga ser. Exasperatae Corner (1960)). — This group differs from the others in the drupaceous fruitlets. It is represented by three species in the eastern part of the Malesian region: F. montana, F. sandanakana, and F. subsidens. Ficus montana extends to Myanmar and is clearly related to F. andamanica Corner (1960) from the Andaman and Nicobar Islands. The presence of the same type of fruitlets (mostly with tuberculate endocarp bodies) link this group of Asian species to the nine Sycidium species from Madagascar (and adjacent islands) and continental Africa; one of them, F. exasperata, also occurs in Sri Lanka and India. The whole group of species with drupaceous fruitlets is distinctly centred in Africa and Madagascar, extending with some species through the Asian mainland to western Malesia and possesses two endemic species in northern Borneo. The whole group shows a morphological variability in habit and leaves that roughly resembles that of the essentially Malesian-Australasian group of species of section Sycidium, but in contrast to the latter group the tepals are always white and often more conspicuously hairy. The F. montana-group (s.l.) differs ecologically from the Malesian-Australasian group in having more shrub species and more species occurring outside forest habitats.
- e. Ficus heterophylla-group (including subsect. Varinga ser. Heterophyllae and ser. Cyrtophylleae, Corner 1960). — The group comprises seven species of shrubs (or treelets) with short-petiolate distichous leaves. It includes three species found in the Malesian region: F. asperiuscula, F. heterophylla, and F. leptogramma, the first and third are confined to this region and the second extends to the Asian mainland, where also two other species included in subsect. Varinga by Corner (1960, 1965), F. cyrtophylla (Wall. ex Miq.) Miq. and F. praetermissa Corner (1960), occur. It is not quite clear whether the two Sino-Himalayan species F. henryi and F. subincisa, ranked in subg. Ficus ser. Sinosysyceae (Corner 1960) and presently referred to the F. ulmifolia-group, should be rather put into the F. heterophylla-group. The distribution of this group is linked to the Asian mainland and western Malesia. The group does not have clear features for delimitation, in particular against the F. ulmifolia-group; these features are: the common presence of a single waxy gland, and if there are two (in the axils of both lateral veins), then they are usually different in size; the solid leafy twigs; the persisting periderm on older twigs; and the absence of features showing intermittent growth. Ficus heterophylla (variable in habit) and F. praetermissa Corner (1960) can be procumbent shrubs and straggling to scrambling shrubs. These habits, the common presence of a single waxy gland, and (presumed) continuous growth, may relate this group to sect. Palaeomorphe. Inclusion of F. exasperata in subsect. Varinga (by Corner 1960) implies a link of the F. heterophylla-group to the African and Madagascan species. This group may, together with the F. montana-group and the group of African and Madagascan species, constitute an entity of the western part of the range of the subgenus, having as its sister-group the entity comprising the F. conocephalifolia-, the F. copiosa-, and the F. ulmifolia-group, based in the eastern part of the range of the subgenus. The western entity and the essentially western Malesian sect. Palaeomorphe may have ancestry in common. In spite of these considerations, the position of the F. heterophylla-group remains somewhat puzzling.