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The Journal of Indian Botany/Volume 1/October 1919/The Indian Species of Eriocaulon

THE INDIAN SPECIES OF ERIOCAULON.

BY

P. F. FYSON, B.A., F.L.S.

Presidency College, Madras.


The difficulty of identifying from published descriptions the species of ERIOCAULON found in South India led me finally to attempt a revision of the Indian species from material available in the herbaria of this country. A full account with photographs of the type or other sheet of most of the species will appear in the Records of the Botanical Survey of India, but as it seems probable that it will not be published for some considerable time, a short resume now may not be out of place, and may perhaps be of assistance to collectors of this difficult genus.

The genus was monographed in Das Pflanzenreich in 1903, by Ruhland, who separated and arranged the species according to the number of the parts in each whorl of the flower, to the geographical distribution (Old and New Worlds) and to minor characters of various kinds. Taking only the species which occur in India it appears to me that they fall naturally into eight groups, or sub-genera, in each of which a tendency to reduction of the floral parts continually shows itself, so that Ruhland's arrangement according to the number of the parts and the perfection of the flower cuts across the natural groupings. The arrangement in the Flora of British India follows in some respects more natural lines, but too much stress is laid in most of the descriptions on unimportant characters, and the possession by some species of white or yellow anthers, instead of the more usual black, is altogether ignored.

The least modified species appear to be glabrous plants with short discoid stem, narrow leaves, and peduncles bearing heads of male and female flowers, each subtended by a black slightly hairy floral bract ; and having in the male three sepals combined into a spathe-like calyx split on the upper side, a funnel-shaped corolla with three equal lobes and six stamens with black anthers ; and in the female three equal, boat-shaped sepals, three equal oblanceolate ciliate petals, a superior ovary with three one-seeded lobe3, and a three-fid style. From this fairly primitive type development appears to have proceeded along several different lines to produce groups of species as follows : —

I. SIMPLICES. Land or water-plants with the characters given above. Some of the species have (a) glabrous, some {b) villous receptacle. In both sub-groups reduction occurs in the female sepals, one of which may be reduced to a mere bristle or be absent altogether. This reduction, which is found also in other groups, is clearly correlat- ed with the compression of the flowers in the head, for it is the medial, ad-axial, sepal which is reduced in each case.

To this group belong (a) E. Geoffreyi sp. nov. (fig. 2), E. Collettii Hook, f., E. barba-caprae sp. nov., E. gregatum Koern., E. nepalense Presc, E. Pumilio Hook, f., E. truncatum Ham., E. Trimeni Hook, f., and E. Duthiei Hook f . ; (b) E. xeranihemwi Mart., E. luzulae folium Mart., E. Thivaitesii Koern., E. achiton Koern., E. quinquangulare L., E. roseum sp. nov., E. trilobum Ham., E. collinum Hook, f., E. Diana sp. nov., and E. Sedgwickii sp. nov.

II. SETACEUM. Submerged plants with elongate stems and linear leaves. The heads and flowers are small, but as in I. To this belong E, setaceum Linn. (not of F.B.I.) and E. intermedium Koern. (incl. E. setaceum of F. B. I.)

III. HIRSUTAE. Whole plant hairy, otherwise as in lb. To this belong E. Brownianum Mart. (incl. E. nilagirense Steud.), E. robust obroivnianum Ruhl, E. graeile Mart., E. Bhodae sp. nov., E. Wightianum Mart, (incl. E. Helferi Hook f.) and E. lanceolatum Miq.

IV. ANISOPETALAE. One male petal much enlarged and projecting beyond so as to hide the floral bracts (fig. 4), otherwise as in lb. To this belong E. odor at urn Dalx., E. longicuspis Hook, f., (incl. E. polycephalum Hook, f.,) E. atratum Koern., E. ceylanicum Koern. (incl. E. subcaulescens Hook, f.), E. caulescens Steud. (incl. E. robust um Hook, f.) and E. cristatum Mart.

V. SCARIOSAE. Involucral and floral bracts glabrous and scarious, otherwise as in lb. To this belong E. oryzetorum Mart., E. Hamiltonianum Mart., and E. Ediuardii sp. nov.

VI. CRISTATO-SEPALAE. Female sepals strongly boat shap- ed, and crested or swollen along the keeli ; otherwise as in I. E. Margaretae sp. nov., E. Eleanorae sp. nov., E. minutum Hook, f., E. stellulatum Koern., E. echinulatimi Mart., E. cuspidatum Dalz., E. sexangulare L. (incl. E. longifolium Nees.) and E. Thomasi sp. nov. The last three species having thick rather than crested keels should possibly be separated into another group, but only an examination of species of other countries could determine this. The group appears to have its centre in north South America. Considerable reduction in sepals and petals occurs (figs. 5, 6, 7).

VII. CONNATO-SEPALAE. The female sepals are connected into a spathe like calyx, like the male of other groups. E. alpestre Hook, f. (fig. 8). A small group apparently confined to China, Japan and the

Tibetan Himalayas, and quite distinct from any other Indian species.

VIII. LEUCANTHERAE. The anthers are white or yellow ; otherwise as in lb. Many are water plants, with linear leaves. The group should probably be considered as of equal rank to the rest of the groups taken together. To -it belong E. horsley-kunda sp. nov., E. breviscapon Koern., E. rivulare Dalz., E. miscrum Koern., (incl E. mitophyllum Hook, f.), E. Huvatile Trimen., E. Siebolclianum Sieb. et Zucc. (Figs. 9, 10, 11.)

Many of the characters on which stress is laid in the published descriptions of species, such as the twisting of the scapes or the length of the pedicel, are either common to all species or dependant on age, and are therefore only an encumbrance to critical definition. Leaving these on one side and confining attention to the characters given above and their modifications, the species are found to be much more easily separable than has hitherto appeared. Following on this it is clear that some of the species have in the past been given far too wide a range of distribution, because of faulty identification and consequent confusion with other species. Thus E. luzulaefolium Mart., given in the F.B.I, and other works as occurring through- out India, is confined to the hilly tracts of Eastern Bengal and the Shan states ; E. quinquangulare L belongs only to South India, and chiefly to the eastern side ; and its place in Bengal is taken by E. trilobum, which does not occur in the Peninsula.

Several new species are described, but it is recognised that some at least of these may not be new, for I have failed to identify several described by Ruhland and others. Perhaps the strangest of the latter is E. melaleucum Mart., a species whiuh occurs in the F.B.I, and in other floras but has no named representative in the Herbarium of the Royal Botanic Gardens, or in any other Indian Herbarium. Ruhland describes the anthers as white, and my E. Horsley-kundae (fig. 9) may therefore be it, but Martius' original description is not quite definite enough and those of subsequent writers point to the probability of it having been confused with other species.

An interesting evolutionary fact comes to light in the existence of parallel development in different strains. Thus a reduction of one female sepal from a boat-shaped to a flat scale occurs as E. collinum crosses from S. India to Ceylon ; E. trilobum in Bengal differs from E. quinquangulare in S. India hardly at all, except in somewhat more pronounced a reduction ; and both these have their counterparts in E. Diana (fig. 3) in the Bombay Presidency, where every stage of this re- duction can be seen. Again a lengthening of the involucral bracts so that the head appears rayed occurs in Group 1 in E. Diana, in the stock of E. quinquangulare as var. Martiana (mihi) and as E. roseum mihi) (fig. 13) and in E. xeranthemum; in group III it occurs in var. Kurzii of E. gracile, and in group V. in E. Edwardii. A reduc- tion of the female petals till they are only as wide as the hairs which spring from the base and form with them a tuft or brush, occurs in group I. in E. Thwaitesii, and in group VI. in E sexangulare (see fig. 7). From the former species arose E. achiton with no petals at all. The submerged habit is correlated with filiform leaves in group I. in E. gregatum and E. barba-caprae, and in group VIII in a series begin- ning with E. breoiscapon and ending with E. fluvatile ; while in group II it is accompanied by a great lengthening of the stem.

This work was only rendered possible by the kindness of the officers in charge of the herbaria in the Eoyal Botanic Gardens, Calcutta (which has most of the types) ; the Agricultural College, Coimbatore ; the College of Science, Poona ; the Forest College, Dehra Dunn ; and the Eoyal Botanic Gardens, Peradiniya, in placing their material at my disposal for examination, and to them my thanks are due and warmly tendered ; but particularly to Lt.-Col. A. T. Gage, the Director of the Botanical Survey of India, and Superintendent of the Eoyal Botanic Gardens, Calcutta whose collection is the largest and contains most ' types '.

Explanation of the Figures Fig. 1. Male flower of E. quinquangularc L. Fig. 2. Female flower of E. do. do. Fig. 3. Do. do. E. trilobum Ham. Fig. 4. Male do. E. caitlescens Steud. Fig. 5. Female do. E. Eleanor a sp. nov. Fig. 6. Do. do. E. minutum Hook Fig. 7. Do. do. E. Thomasi sp. nov. Fig. 8. Do. do. E. alpestre Hook. f. Fig. 9. Male do. E. horsley-Jcimda sp. nov. Fig. 10. Do. do. E. Sieboldianum Sieb et Zucc Fig. 1L. Female do. E. do. do. Fig. 12. Head of ... E. Diana sp. nov. Fig. 13. Do. ... E. roseum sp. nov.