2o6 Graminece. [Rottboeiiia. 



by linear-lanceolate glume I with a 2-mucronulate tip, by glume II being 

 aristulate, and IV entire. I find, however, that glume I is usually simply 

 acute, II often not aristulate, and IV bilobed in both the sessile and 

 pedicelled spikelets. He has further a subsp. seminuda from Ceylon, 

 Thwaites (C. P. 411, ex parte), which I do not find in the Peradeniya 

 Herbarium, where C. P. 411 is all Andropogon pertusus. The characters 

 of subsp. seminudus are to have the joints of the spike with cilia 4-6 

 times longer than the joint itself on one side only, glume I bimucronulate, 

 callus nearly glabrous, awn of glume II as long as the glume or one-third 

 shorter, and glume IV entire. As far as the Ceylon form of P. ciliata is 

 concerned, I do not think that the above characters constitute even well- 

 marked varieties. 



30. ROTTBOELLIA, Linn. f. 



Annual or perennial grasses of various habit; stems leafy; 



1. narrow, flat; spikes solitary, racemose or subpanicled, rhachis 



articulate, internodes terete or compressed, each bearing a 



pair of dissimilar awnless spikelets, a lower i-2-fld., usually 



bisexual, sessile, sunk in a cavity of the internode, the upper 



pedicelled, male or neuter, with the pedicel free or adnate to 



the side of the internode; sessile spikelet as long as or shorter 



than the internode; glumes 4, I coriaceous, ovate or oblong, 



flat or convex, closing the mouth of the cavity, margins 



narrowly incurved, II very thin, 1-3-veined, III hyaline, 



paleate or not, neuter, IV hyaline, paleate, bisexual ; lodicules 



quadrate or cuneate; anth. 3, linear; styles rather distant at 



the base and stigmas short; upper or pedicelled spikelet 



smaller than the sessile; glume I usually herbaceous, II-IV 



much as in the male spikelets; grain oblong, compressed. — 



Sp. about 30; 18 in Fl. B. Ind. 



In the above description R. perforata is not included. After further 

 examination of it I think that the genus Mnesithea, Kunth, should be 

 maintained. 



Rhachis of spike not fragile 1. R. COMPRESSA. 



Rhachis of spike fragile. 



Leaf-base narrow, rounded . . . . . 2. R. exaltata. 



Leaf-base broad, cordate . . . ■ . . 3. R. NlGRESCENS. 



1. R. compressa, Linn. f. Supfil. 114 (1781). 



Moon, Cat. 9. Hemarthria compressa, Kunth ; Thw. Enum. 364. 



C. P. 3254- 



Fl. B. Ind. vii. 153 (var. genuind). Roxb. Cor. PI. ii. t. 156 (R. glabra). 



Stem 2-5 ft., decumbent and rooting below, branched, 

 slender or stout, compressed, ribbed, glabrous, leafy; 1. 1-5 

 by \-\ in., linear, acuminate, fiat, glabrous, flaccid when very 

 elongate, base rounded, margins scabrid, midrib and veins 

 slender, sheaths shorter than the internodes, compressed, 



