284 Jour., Born, Nat, Hist. Soc, Vol. XXXI I, No, 2. [Oct. 20, 1927, 



We have not included the synonyms which Stapf Fl. Trop. Afr. ix, 95, has 

 given under 5". spontanetim var. csgyptiacum, Hack- as we are not in a position 

 to judge whether it is a good variety or not. According to Hole the African forms 

 placed under var. csgypliacum differ from the Indian plants chiefly by their" 

 slightly larger spikelets. But he finds that this difference is very slight and that 

 it fails in the case of some African specimens. ' Considering the great variabili- 

 ty of the species in India it seems possible that a more complete knowledge of the 

 African plant will prove cegyptiacum to be merely one of the several oecological 

 forms which are defined by inconstant characters and which are connected by 

 numerous intermediates.' 



Description .-—Stem erect or decumbent at the base, reaching up to 6 m. in 

 height and 15 mm. in diam., solid above,, fistular below, terete, indistinctly 

 striate, usually pruinose when young, polished when old, silky below the pani- 

 cle and minutely silky below the upper leaf-insertions, glabrous or minutely 

 pubescent below the lower leaf-insertions. Leaf-sheath longer than proper 

 internode, often with reddish or purplish blotches, villous at mouth, often 

 minutely pubescent at base, otherwise glabrous or with scattered appressed hairs, 

 sulcate. Blade erect, of uppermost leaf of flowering culm usually long, varying 

 from 5 cm. to 90 cm. in length, of lower leaves up to 12 m. and even 2 m., 

 usually very narrow, often not exceeding 1*5 mm. in width and then consisting 

 of a very narrowly margined cancavo-convex midrib, but also attaining a width 

 of 16 mm. glaucous, midrib white, margin scabrid, often villous above at base 

 immediately behind the ligule. Ligule ovate or deltoid, base often sub-auricled, 

 membranous, subacute or subtruncate, often fimbriate when old, up to 6 mm. 

 high, minutely silky dorsally and ciliate. Flowering panicle 15-60 cm. long, 

 conical or lanceolate to oblong branches horizontally spreading or slightly 

 ascending, usually reddish or purplish, with the callus hairs closely appressed to 

 the branches of the panicle ; primary rhachis sulcate, silky with long white hairs ; 

 primary branches subverticillate, simple or compound. Spikelets in pairs, one 

 pedicelled and one sessile on the capillary jointed branches and bran chiefs, aw nless, 

 lanceolate, 2-5 mm. long, sessile and pedicelled similar, each one-flowered 

 and hermaphrodite, pedicelled fruiting spikelet falling from the pedicel, the 

 sessile spikelet falling later with the attached pedicel and joint of axis ; joint of 

 axis longer or shorter than sessile spikelet, villous on margins, or on margins 

 and dorsally ; pedicel \-\\ the length of the sessile spikelet, but usually shorter 

 than spikelet, glabrous or ciliate, shorter than proper joint; callus-hairs white, 

 from \\-l times as long as sessile spikelet. Lower involucral glume lanceolate, 

 the basal third thickened, becoming hard and polished in fruit and more or less 

 brown in colour, the upper two-thirds membranous hyaline, with 2 lateral nerves 

 from which the margin is inflexed ; apex entire or minutely bidentate ; margin 

 ciliate ; dorsally with the upper two-thirds minutely appressed-pubescent. Upper 

 involucral glume broad-lanceolate, similar to the lower, but subkeeled with one 

 central nerve ; apex sometimes mucronate ; margin inflexed and long— ciliate. 

 Lower floral glume hyaline, nerveless, shorter than upper involucral glume, ovate- 

 lanceolate, long— ciliate, minutely pubescent above dorsally. Upper floral 

 glume minute, linear, ciliate, hyaline, sometimes 0. Pale minute, ovate, 

 ciliate, often shorter than the lodicules. Lodicules 2, cuneate, glabrous or 

 ciliate at apex. Anthers 3, yellow, turning brown. Stigmas 2, purple. 



'The horizontally spreading callus-hairs of the fruiting spikelet form an 

 efficient parachute which aids its distribution by wind. The hairs of neighbouring 

 spikelets becoming entangled together, characteristic flocculent masses of several 

 spikelets are often seen being carried by the wind or hanging on the adjacent 

 vegetation . ' (H ole) . 



As good field characters we may mention the narrow leaves and slender culms,, 

 the long callus-hairs and the brown coriaceous base of the involucral glumes. 



This is a very variable species, and Hole does not think that we are justified in 

 making different sub-species or varieties. He distinguishes 3 ecological forms : 



(a) The dry sandy soil-form, a xerophilous type The culms are slender, 



erect and tufted, usually less than 5 mm. diam. The leaves 

 exceedingly narrow, sometimes only a little more than 1 mm. wide. 

 The callus-hairs not less than 3| times the length of the spikelet. 



(b) The swamp form, a hygrophilous type, found in marshes and swamps 



with an abundance of available moisture more or less throughout the 

 year. The culms are stout, 5-15 mm. diam., usually decumbent at 

 base and not tufted. Leaves broad, reaching a width of 17 mm, 



[4] 



