16 MB. C. B. CLABKE ON INDIAN SPECIES OF CTPEBTJS. 



in the series C. Andersonii, C. Seemannianus, &c, digitate spikes 

 on each ray appear equally constant ; but of these species I have 

 seen few examples ; of C. urnbellatus, Benth., thousands (in a 

 literal sense). 



The rays and radioles of the umbel are terete, triangular, or 

 compressed, much as the culms ; very generally glabrous, but 

 hairy in the few species with hairy culms. The rhachis of the 

 spikes is generally angular, deeply grooved, and occasionally 

 minutely scabrous. In C.pilosus the scabrousness of the angles of 

 the rhachis of the spikes becomes " pilose ;" i. e. the rough points 

 come very close together, and take the form of very short brownish 

 hairs. This distinguishes the species from all others readily 

 except from C. procerus, in which the rhachis of the spikes is some- 

 times glabrous, usually scabrous, sometimes " pilose," or at least 

 un distinguishable from that of C.pilosus. 



(6) The Bhachilla. of the Spikelet. 



The examination of the rhachilla, especially after some of the 

 lower glumes have fallen off, is a convenient way of observing the 

 structure of the spikelet. A glance at the rhachilla of Isolepis 

 Micheliana will show how far the plant must be removed from 

 Cyperus, in which the notches are on two opposite sides of the 

 compressed (or subquadrate) rhachilla ; and a similar glance will 

 show Cyperus Banko, Steudel, to be an Isolepis. The great variety 

 in the rhachilla is seen by comparing a few common species, as 

 C. puncticulatus, Vahl (fig. 30), C. Monti, Linn. (fig. 29), C. luci- 

 dulus, Klein (fig. 28), C. auricomus, Sieber (fig. 31), C.flexuosus, 

 Vahl, C. wmbellatus, Benth. ; and the differences are not merely 

 manifest, but constant ; and are treated as of importance, for 

 species and for groups, by Kunth and Boeckeler. The bases of 

 the glumes are decurrent on the rhachilla, forming two lines of 

 "wings" to it on either face. These wings are in some species 

 (as in many of the subgenus Pycreus) obsolete ; in others, as in 

 C. compressus, they unite to form narrow continuous scarious 

 wings running down the whole length of the spikelet ; and such 

 wings are in many species broader, sometimes purple-spotted. In 

 other species the wing is not continuous (at least not in subequal 

 breadth); frequently the base, sometimes nearly the whole, of 

 the nut, lodged in the notch of the rhachilla, is held on each side 

 by the widened wing of the rhachilla. In most species the wing 

 separates off from the base of the glume, long before the nut is 



