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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



extensions are formed, however . The mesophyll consists wholly of spongy paren- 

 chyma cells, some of which become lightly sclerified at maturity. Although the 

 leaves of 8. condensata (fig. 13) are broader, the anatomy is much the same as 

 that of S. cy mb i folia. Xo hypodermis is present, however, and the subepidermal 

 sclerenchyma in the leaf margins is not so extensive as that of 8. cymbi folia. In 

 Stomatochaeta cylindrica (fig. 14), a sclerified epidermis is present on the Lower 

 surface, but on the adaxial surface a sclerified hypodermis and non-sclerified 

 epidermis are formed. In addition, a division into four layers of loosely arranged 

 palisade and nine layers of spongy parenchyma occurs in the mesophyll of 8. 

 cylindrica leaves. The sclerenchyma of the margin (fig. 14, below) is approxi- 

 mately as in 8. condensata. Details of the epidemis of 8. cylindrica are shown 

 in figures 15 and 16. In figure 15, a surface view of the abaxial epidermis shows 

 the thick-walled sclereids, often irregular in outline, which compose the entire 

 epidermis with the exception of the guard cells and a single circle of cells 

 surrounding each stoma. Guard cells are slightly external to adjacent epidermal 

 cells, and the portions of guard cells which overlap epidermal cells are shown 

 by dotted lines. Figure 16 illustrates the extremely thick cuticle which occurs 

 on both surfaces of leaves of all species of Stomatochaeta studied. Also note- 

 worthy is the occurrence of sunken hairs; these trichomes consist of a tier of 

 rather short, wide cells, and do not project above the surface in mature leaves. 

 Such abortive hairs, sunken into cuticle, are apparently characteristic of several 

 taxa investigated, since they were observed also in Stenopadus and Qnclchia. 



The genus Chimantaea (figs. 17-19) shows a highly individual series of fea- 

 tures. Characters common to all species studied include an unsclerified adaxial 

 epidermis with extremely thick cuticle, a prominent hypodermis at least two 

 cells in thickness, subhypodermal sclereids with extremely thick walls scattered 

 among the palisade cells, presence of spongy parenchyma, lower epidermis with 

 relatively thin cuticle and exserted stomata, and an abundant development of 

 uniseriate thick-walled trichomes on the lower surface. 



Chimantaea mirabUis (figs. 17, 18) has narrow leaves with inrolled margins. 

 The epidermal cells are large, usually tapered toward the outside surface. The 

 hypodermis, which is 2-4 cells in thickness, is composed of sclereids. About 3 

 layers of palisade and three of spongy parenchyma are present. Occasional in 

 the palisade are enormous thick- walled sclereids, which span the distance between 

 hypodermis and spongy parenchyma. The bundle sheath of veins consists of 

 thin-wallet sclereids, and although these cells are continuous with the hypo- 

 dermis, which is composed of similar cells, such contact is not made between 

 vein sheaths and the lower epidermis of larger veins. Consequently, sheath exten- 

 sions cannot be said to be present. 



Although the leaves of Chimantaea mirabilis show the most extreme speciali- 

 zation in their inrolled margins and exceptional developments of sclerenchyma. 

 the other species also show a degree of expression of such features. Chimantaea 

 si milis (fig 19), C. rupicola, and C. lanocaulis agree in having small epidermal 

 cells, which are flat rather than tapered. The hypodermis in these species is 

 formed of sclerenchyma much more thin-walled than in C. mirabilis, although 

 it is wider, consisting of 4 or 5 cell-layers. Thick-walled mesophyll sclereids are 

 abundant, usually occurring in groups. Such sclereids are not as long as the width 

 of the palidsade, however. In all three species, approximately five layers of pali- 

 sade and five of spongy parenchyma are present. The foliar anatomy of C him an- 



