MB. 0. B. CLABKE ON INDIAN SPECIES OF CTPERUS. 5 



It must not be inferred, however, that the characters of the 

 rhizome are generally useful in this genus for separating closely 

 allied species ; the contrary is the case, e. g. in G. umbellatus and 

 its numerous subspecies and allied species the rhizome is nearly 

 the same ; while in the long series of forms included by Boeckeler 

 under G. polystachyus he says the root is fibrous, or there is a 

 short rhizome, or the rhizome is elongate, woody ; it is, I believe, 

 always perennial. Again, in the series of plants allied to C. ele- 

 gans, Linn., the rhizome is generally much the same. 



This leads us to the question how far we can utilize the rhizome 

 for characterizing groups higher than species ; and the answer is, 

 as so often in botany, Sometimes we can, sometimes we cannot. 

 In G. conglomeratus and its allies the main roots are densely 

 clothed on all sides with rootlets so as to appear thick and woolly ; 

 the character of roots (thick, woolly) defines a very natural group, 

 to which belongs C. proteinolepis, Steud., removed by Boeckeler to 

 another group. The forms of the G. conglomeratus group of 

 Boeckeler are indeed so closely allied that Boissier (probably 

 rightly) unites, under the old 0. conglomeratus, several of them 

 admitted as species by Boeckeler. 



The species of the group Corymbosi of Boeckeler (G. rotundus, 

 G. longus, &c.) are connected naturally by the stolons or creeping 

 rhizomes. G. tenuiculmis, Boeck. (=C lutidulus. Klein), should 

 be placed next G. compressus ; and G. sphacelatus, because of 

 its fibrous root, I think should not be arranged here, nor the 

 American G. Icetus, G. dissolutus. 



The whole of the Exaltati (in which I include the Papyri) are 

 without stolons : the stout culms are generally solitary ; but as 

 the culm dies down after flowering there often appear lateral 

 suberect shoots from close to the base ; such shoots also occur in 

 several stoloniferous species, and in some with creeping rhizomes. 

 They may occur, accidentally probably, in nearly every species of 

 the genus ; and though they are generally easily distinguished 

 from stolons, in G. procerus there is a very gradual transition 

 from one to the other. 



The rhizome is thus a character to which we must pay a very 

 great degree of attention in some parts of the genus, and little 

 in others, whether for specific or subsectional sorting. 



The roots of the same species become manifestly thicker, more 

 spongy, wheu the specimen grows in a very wet place. The 

 species that grow in damp woods, like O. elegans, have usually 



