432 T. Holm — Studies in the Cyperacece. 



Finally the perigynium is granular, but not papillose, and 

 possesses three stereomatic strands between the two mestome- 

 bundles ; the external shape of this organ is, as stated above, 

 very different from that of C. holostoma. 



The affinity of C. holostoma, thus, seems to be with C. stylosa 

 and C. Ray nolo 1 sii instead of with C. alpina, when we com- 

 pare the external structure of the spikes, and especially of the 

 perigynium. But from an anatomical point of view the dis- 

 tinction is barely noticeable, and we have, thus, in C. alpina 

 a type that exhibits the same internal structure as the higher 

 developed within the same grex. It must not be forgotten, 

 however, that C. alpina being pleiostachyous represents a higher 

 type than the monostachyous "formse hebetatse" of the other 

 greges. 



Brookland, D.C., April, 1907. 



EXPLANATION OF FIGURES. 



Fig. 1. Epidermis of the culm of C. capitata showing the branched 

 papillae ; x 560. 



Fig. 2. Epidermis of the leaf of same species, x 560. 



Figs. 3-6. Inflorescences of C. holostoma ; If x natural size. 



Fig. 7. Scale of staminate spike of C. holostoma ; magnified. 



Fig. 8. Scale of pistillate spike of same ; magnified. 



Fig. 9. Perigynitim of same ; magnified. 



Fig. 10. Same, transverse section; Ep. = dorsal, Ep.*= ventral epider- 

 mis ; x 820. 



Fig. 11. Transverse section of the root of C. stylosa; Ep.= epidermis; 

 S.=stereids; C.=cortex. x 320. 



Fig. 12. Epidermis of perigynitim of C. stylosa. x 240. 



Fig. 13. Transverse section of the root of C. alpina; Ex.=esodermis ; 

 the other letters as above, x 320. 



