52 INDIAN FOREST MEMOIRS. 



^, eld The narrow leaves and slender culms, the long callus hairs and the brown coriaceous 



Characters. ° 



base of glumes I and II are good field characters. 



B. — Taxonomy. 



45. Hackel l classifies the Indian forms of 

 this species under two sub-species which he defines as follows : — 



Sub-species a. indicum. — Slender. Culm 3 — 4 mm. in diameter. Lamina narrow 



linear (2 — 8 mm. wide). Ligule ovate, sub-acute, often sub-auricled at base. 



Racemes slender, few-flowered. Spikelets 3 — 4 mm. long, callus-hairs white, 



very soft, 4 — 6 times longer than spikelets. 

 Sub-species b. cegyptiacum. — Robust. Culm 4 — 6 mm. in diameter. Lamina broad 



linear (6 — 14 mm. wide). Ligule truncate. Racemes stout, densely flowered. 



Spikelets 4 — 6 mm. long, callus-hairs twice as long as spikelets (or a little 



more) . 



The only Indian form placed by Hackel under mgyiJtiacum is the variety nepalense which 

 he describes as having leaves up to 6 — 10 mm. wide, a linear-oblong panicle, spikelets 4 mm. 

 long and callus-hairs somewhat stiff, white, 2-| times longer than the spikelets. 



The present species varies greatly according to its habitat, as will be seen from the 

 biological and cecological notes given below, and in India the three following cecological 

 forms can be distinguished in the field although, connected as they are by numerous inter- 

 mediate forms, their separate definition under different names as sub-species or varieties 

 does not seem advisable : — 



(1) The most xerophilous form found on dry sandy soil. Culms slender, usually less 



than 0-2" in diameter, erect and tufted. Leaves exceedingly narrow, some- 

 times only 0-05" wide, callus-hairs not less than 3^ times the spikelet. This 

 may for the present be distinguished as the sand-form. 



(2) The most hygrophilous form found in swamps and marshes where there is an 



abundance of available moisture more or less throughout the year. Culms 

 stout, 0-2" to 0-6" in diameter, usually decumbent at base and not tufted, 

 leaves broad attaining a width of 0-7", callus-hairs \\ — %\ times as long as 

 spikelets. 



The fruiting panicle is elongate-elliptic to oblong with its branches usually 

 more persistent than in other forms. 



This includes the var. nepalense of Hackel and may be distinguished as the 

 swamp-form. 



(3) A form intermediate between (1) and (2), usually found on loam, with culms 



more or less decumbent at base and not tufted, but less robust and wjith longer 

 callus-hairs than (2). This may be called the loam-form. 



1 In Monograph. Phanerogam, of DeCandolle, Vol. VI, 1889, p. 114. 



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