BY J. H. MAIDEN AND E. BETCHE. 741 



Eragrostis concinna Steud. 



Paroo River flats, on white sandy soil (A. W. Mullen; April, 

 1906). 



A Central Australian grass, previously recorded from South 

 Australia, Queensland and North Australia. The grain is not 

 described in the "Flora Australiensis"; it is small, narrow-ovate, 

 pale coloured and quite smooth. 



ROTTBOELLIA TRUNCATA, n sp. (Plate lxix.). 



Yandama, North-western New South Wales (A. W. Mullen; 

 April, 1906). 



A glabrous annual about 9 inches high, with erect somewhat 

 geniculate flattened stems, branched chiefly at the base. Leaves 

 2 to above 4 inches long, about 1 1 lines broad, tapering to a point, 

 the sheath long, rather loose, striate as the blade, and with a 

 short ciliate ligula. Spikelets mostly in threes, rarely in pairs, 

 the lowest group occasionally in fours, all sessile on the alternate 

 sides of a flat and very brittle rhachis, closely appressed so as to 

 form a false spike enclosed when young in the leaf- sheath. Length 

 of the false spike about 3 inches or more, but the articulate 

 rhachis is so fragile that it breaks up into articles, and a whole 

 spike can rarely be seen in dry specimens. When the number of 

 spikelets in the group is 4, one is sessile on the base and the 

 others on the alternate sides of a flattened rhachis prolonged 

 beyond the insertion of the last spikelet, so that no spikelet is 

 terminal, the whole resembling the false spike in miniature, with 

 single spikelets instead of groups of spikelets. The arrangement 

 of the spikelets is the same in the triplets, and, when in pairs, 

 one spikelet is sessile and the other on a flattened pedicel, as in 

 typical Rottboellia. Outer glume of the sessile spikelet broad- 

 linear, flat, truncate, about I line long, of rather thin texture, 

 pale-coloured, but striate with 4 to 6 green ribs not reaching 

 quite to the truncate apex, giving it a callous appearance 

 Second glume at least \ longer than the outer one, but of similar 

 shape, the truncate apex rather narrower and somewhat jagged, 

 the texture firmer and the green ribs fewer. Third glume nearly 



