T. Holm — Studies in the Oyperaeew. 



Art. III. — Studies in the Cyperacece ; by Theo. Holm. 

 VIII. On the anatomy of some North American species of 

 Scleria. With figures in the text, drawn by author. 



Having discussed the composition of the inflorescence in a 

 previous article,* let us pass to examine the anatomical struc- 

 ture of some of our native species : S. pauciflora Muhl., S. 

 triglomerata Michx., S. oligantha Michx., S. Baldwini Steud., 

 S. ciliata Michx., S. filiformis Swtz., S. JElliottii Chapm., S. 

 Torreyana Walp., 8. reticularis Michx., S. hirtella Swtz. and 

 S. verticillata Muhl. 



The root. 



All our species are perennial and the roots are generally very 

 strong and develop especially from the lower side of the 

 rhizome ; they possess much the same structure as has been 

 described before as characteristic of roots of other genera of 

 this large order, but differ from these, however, by the develop- 

 ment of the innermost three or four layers of the bark-paren- 

 chyrna into a sheath of very thick-walled cells, which surrounds 

 the endodermis. This sheath, in connection with the very 

 thick-walled endodermis, forms a very strong mechanical sup- 

 port to the central- cylinder. Otherwise the root shows an 

 epidermis of usual structure, a hypoderm and an outer bark 

 with large lacunes from the tangential collapsing of the cells, 

 in contrast to the inner layers (B 

 in fig. 1), which, as described 

 above, forms a very solid tissue. 



The endodermis represents a 

 typical O-endodermis, and sur- 

 rounds a pericambium of normal 

 structure. There are several large 

 vessels in alternation with groups 

 of leptome, and the innermost ^M^j^^ 

 part of the central cylinder is xXJ-J^JxTq? „ ..? 

 occupied by a large mass of thick- p IG . i. Root of s. pauciflora; 



walled conjunctive tissue. transverse section. B, inner bark; 



This Structure of the root was End endodermis; P, pericambium. 

 , , . • i- . x 400. 



observed in species from various 



localities ; from low, swampy ground and from dry, sandy soil 



in High Pine woods of subtropical Florida. 



*This Journal, vol. v, January, 1898, p. 41. 



