.Dimeria.~\ Graminece. 195 



hyaline, ciliate, epaleate, IV hyaline, complicate, oblong, bifid, 

 awned in the sinus, awn capillary, column short, palea minute 

 or o; lodicules o or most minute; stam. 2, anth. long or short; 

 styles short, stigmas short, laterally exserted ; grain linear, 

 compressed. — Sp. 18; 12 in Fl. B. Ind. 



The fine specimens of this genus in the Peradeniya Herbarium have 

 enabled me to improve the description of the Ceylon species given in 

 Fl. B. Ind., and make some important corrections. Nevertheless, much 

 more ample material is required before the species can be regarded as 

 satisfactorily established, for the characters taken from the rhachis of the 

 spikes and the glumes are liable to considerable variation. I am not 

 satisfied that the division of the species into annual and perennial is 

 sound, being derived from dried specimens only. It might be better to 

 divide them primarily by the number of spikes, as follows : — 



Spikes invariably solitary : — D. pusilla, D. Thwaitesii. 



Spikes 2-3, very rarely solitary : — D. pubescens, D. Lehmanni, D. 

 fuscesceus, D. Trimeni. 



Spikes many : — D. gracilis. 



Lastly, as regards the distribution of the species in Ceylon, I have 

 little or no information, the Herbarium specimens being from isolated or 

 very few localities, and these not always to be found in any accessible 

 map of the island. 



Annuals. 



Keel of glume II winged. 



Glume II acuminate or awned. 



Glume II awned. . . . 1. D. pusilla. 

 Glume II not awned . . . 2. D. pubescens. 

 Glume II obtuse. 

 Glume IV awned . . . 3. D. Lehmanni. 

 Glume IV not awned D. Lehmanni, var. mutica. 



Keel of glume II not winged . . 4. D. Thwaitesii. 

 Perennials. 

 Spikes 2 or 3. 



Rhachis of spike filiform, glabrous 5. D. FUSCESCENS. 

 Rhachis of spike flattened, ciliate . 6. D. Trimeni. 

 Spikes 3-many 7. D. GRACILIS. 



1. D. pusilla, Thw. Enum. 369 (1 

 Hack. Monogr. Androp. 78. C. P. 957. 

 Fl. B. Ind. vii. 103 (excl. var. pallida). 



Annual; stems tufted, 6-18 in. high, very slender, leafy, 

 simple or branched; 1. 1-3 by to - ! i n -> linear, acuminate, 

 quite smooth, glabrous, midrib slender, sheath smooth, 

 auricles ciliolate, ligule very short, truncate; spike solitary, 

 i|-2 in. long, rhachis filiform, trigonous, internodes very 

 short, margins smooth or scaberulous; spikelets i in. without 

 the awns, sessile or very shortly pedicelled, callus as long as 

 the pedicel, thickly bearded; glumes I and II sparsely or 

 copiously hirsute, I linear, acuminate, keel scabrid and ciliate, 

 II rather longer, narrowly oblong, acuminate, margins ciliate, 



