MB. C. B. CLABKE ON INDIAN SPECIES OF CYPEBUS. 11 



The bracts are usually 3-6 in number, occasionally 3-10. In 

 G cequalis and G. Papyrus, where the number of rays may reach 

 100, the number of bracts is not increased at all in proportion. 



(5) The Umbel. 



In Cyperus the inflorescence is always an umbel, i. e., as we 

 have seen, a congested corymb, which may be reduced to a dense 

 capitulum, or may be compound or supradecompound ; in the 

 compound umbels the umbellules are similar to the main umbel, 

 but often less congested, till in many species they lose the um- 

 bellate appearance altogether, and can only be described as open 

 corymbs, often with patent or divaricate branches. 



The corymb is always very much depressed, so that the nodes 

 between its upper branches are obsolete, while the branches 

 themselves gradually increase in length from the uppermost, 

 which is 0, to the lowest, which may be 0-3 decim. The main 

 umbel thus has more or less unequal branches with a sessile 

 spike in its centre, and the secondary, tertiary, &c. umbels take 

 the same form which gives Cyperus its distinctive appearance. 

 Perhaps the most aberrant species in the genus in habit are thus 

 G. Papyrus and G. cequalis, in which we have a great number (up 

 to 100) primary rays (instead of the usual 3-10), and these all 

 very nearly equal in length ; and in these two species the central 

 sessile spike is depauperate amid the crowded bases of the rays 

 or altogether suppressed. Bnt throughout the genus the struc- 

 ture of the umbel is most essentially and minutely the same ; 

 and great differences in its aspect are caused by mere variations 

 in the length (and angle of divergence) of the primary, secondary, 

 &c. rays. This identity of real character has always been a source 

 of difficulty in the verbal definition of species and subsections of 

 Gyperus, in which all authors are agreed in regarding the umbel 

 as a character of great weight. 



The development of the umbel varies enormously in nearly all 

 the compound species ; i. e. those species which, when fully de- 

 veloped, have a compound or decompound umbel, produce in 

 numerous examples only a simple or small umbel. Thus C. rotun- 

 dus, Linn., has ordinarily a compound (often lax) umbel with very 

 numerous spikelets ; but small examples often have a simple umbel 

 or even a single spike ; and a form which I have called form " Sal- 

 tola " is common near the sea (as at Calcutta), in which each 



