T. Holm — Studies in the Cyperacece. 431 



Carex Raynoldsii Dew. 



The structure of this species agrees in most respects with 

 that of C. stylosa, but the following distinctions may be men- 

 tioned. The culm is sharply triangular, but glabrous, and very 

 robust ; the homogenous cortical parenchyma is traversed by 

 very wide lacunes, and the stereome is much stronger developed 

 than in the former species. The thin-walled pith is hollow. 

 The very broad leaves are glabrous and flat ; epidermis is thin- 

 walled on both faces and the outer cell-walls are extended so as 

 to form low papillae, esjDecially on the dorsal face ; the stomata 

 are sunk, and the air chamber is shallow, but wide. No palisades 

 are developed in the chlorenchyma, and the stereome is well 

 represented on both faces of the mestome-strands besides in 

 the leaf-margins. 



The perigynium is very thin and perfectly glabrous ; the 

 dorsal epidermis is moderately thick-walled in contrast to the 

 ventral, and the chlorenchyma is very sparingly represented. 

 There are only two mestome-strands, but about twenty narrow 

 strands of stereome between these. 



In comparing the structure of these species : C. holostoma, 

 stylosa and Raynoldsii, we notice the very prominent develop- 

 ment of papillae in C. holostoma, to some extent also in C. 

 stylosa, but not at all in C. Raynoldsii. Furthermore the 

 presence of almost typical palisades in the leaf of C. stylosa in 

 contrast to the homogenous chlorenchyma in the other species. 

 The bulliform cells occur only as one band above the midrib, 

 of two strata in C. stylosa, but of only one in the other species. 



The perigynium is glabrous in C. Raynoldsii, but granular 

 in the others, and the presence of many isolated stereome-strands 

 is characteristic of this same species. 



If we extend the comparison to C. alpina Sw., which rep- 

 resents a lower type of the Melananthm, we do not observe 

 any character in anatomical respect by which this species may 

 be distinguished from the more evolute C. holostoma or its 

 nearest allies. The roots (fig. 13) possess an exodermis, and 

 four strata of stereids, while the cortex consists of eight layers 

 of thin-walled cells, tangentially collapsed. The encloclermis is 

 heavily thickened, and the pericambium is interrupted by all 

 the protohadrome-vessels. The culm is obtusely triangular and 

 glabrous, with the cortex traversed by wide lacunes. The 

 mestome-bundles are arranged in one band and supported by 

 thick-walled stereome. The leaves are scabrous from obtuse 

 papillae, and the stomata are raised a little above the adjoining- 

 epidermis; on the ventral face the chlorenchyma shows one 

 stratum of almost typical palisades ; thus the leaf-structure re- 

 sembles that of C. stylosa, and more so than that of C. 

 holostoma. 



