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MEMOIRS QF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



taea is in certain respects like that figured by Marloth (The Flora of South 

 Africa, Vol. 3, Pt. 2, 1932) for another genus of Gochnatinae, Oldenburgia. 

 Chimantaea differs in its thick sclereid-bearing palisade; the palisade of Olden- 

 burgia is narrow and composed of thin-walled cells. The similarities bet ween 

 the two genera probably represent parallel adjustments to xeric situations. 



The other genus of Guayana Gochnatinae, Quelchia (fig. 20) is distinguish- 

 able in its leaf anatomy from the preceding by virtue of the fact that thin- 

 walled sclereids form bundle sheath extensions on the larger veins. The two 

 species studied, Q. bract eata and Q. cardonae, have extensions composed of cells 

 identical in shape and wall thickness to those of the hypodermis. The adaxial 

 hypodermis is approximately two cells in thickness, and a single layer of cells 

 composes the abaxial hypodermis. Cells appearing to be laticiferous by virtue 

 of contents and large size occur in the adaxial hypodermis. A division into three 

 or four layers of palisade and about ten of spongy parenchyma occurs. A promi- 

 nent cuticle is present on both upper and lower epidermis. 



Among Gerberinae, the genus Gongylolepis (figs. 21, 22) is least specialized 

 in its leaf anatomy. From liquid-preserved material of 6r. huachamacari subsp. 

 neblinensis (fig. 21), the distribution of laticiferous cells could be determined. 

 Cells containing latex occur in both upper and lower epidermis, in all layers 

 of the adaxial hypodermis, and in spongy and palisade parenchyma. Gongylo- 

 lepis huachamacari subsp. neblinensis exhibits an advance over other species of 

 the genus in possessing a hypodermis which consists of a single layer of small 

 thick-walled cells, together with two layers of parenchyma only slightly more 

 thick-walled than palisade cells. A bundle sheath extension is present on most 

 veins. Within the bundle sheath, an exceptional development of fibers is seen ; 

 these often extend to both epidermises, and intervene between the phloem and 

 xylem of a vein. Approximately two layers of palisade and seven of spongy 

 parenchyma are characteristic of G. huachamacari snbsp. neblinensis. In G. 

 martiana (fig. 22), a condition more typical of the genus may be observed. One 

 or two layers of hypodermis are present on the adaxial surface. The bundle 

 sheath is highly fibrous, and extends to both surfaces in larger veins, forming 

 extensions. Approximately three palisade and seven spongy layers are present. 



Among species of Gongylolepis investigated which are not illustrated, G. 

 huachamacari and G. bracteata differ from G. martiana in having a thicker leaf, 

 with 4 or 5 hypodermal, three palisade, and about 12 spongy layers. The bundle 

 sheath anof sheath extensions consist of cells like those of the hypodermis, rather 

 than being composed of fibers. Fibers are, however, present immediately adja- 

 cent to the bundles. The spongy cells immediately adjacent to the lower epi- 

 dermis are often thickened, suggesting the development of a hypodermis on the 

 lower surface. Gongylolepis fruticosa, a rather specialized species, shows notable 

 differences in that the leaves are isolateral, with 3-5 layers of hypodermis on 

 each surface, separated by 7 or 8 layers of spongy parenchyma. Bundle sheaths 

 and sheath extensions are as in G. huachamacari. 



The genus Neblinaea, not illustrated, easily fits into the range of variation 

 found in Gongylolepis. The description above of G. huachamacari could be 

 applied to the only species, N. promontorium, except for the narrower hypo- 

 demis (2 cell-layers), palisade (2-3 cells), and spongy tissue (about 5 cells). 



Achnopogon and Duidaea, by contrast, show remarkable specializations. The 

 single species of Achnopogon (fig. 24) has a leaf anatomy basically similar to 



