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MEMOIRS 'OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



high degree of cortex selerification, exceeding even that in Steiiopadus. Because 

 of this combination of features, it is difficult to ally Glossarion with either the 

 gongylolepoid or stenopadoid type. 



Differences among the various genera in respect to periderm origin and 

 abundance are quite evident. Information from approximately comparable stems 

 may be summarized as follows, periderm origin being noted where material 

 permitted : 



Stcnopadus : moderate, origin in third or fourth hypodermal layer 

 Stomatochaeta: scanty, origin in third or fourth hypodermal layer 

 Chimantaea: abundant, successive periderms in young stems 

 Quelchia: moderate, origin in second or third hypodermal layer 

 Gongylolepis : moderate, origin in second hypodermal layer 

 Achnopogon : prominent, origin in first or second hypodermal layer 

 Duidaea: prominent, origin in first or second hypodermal layer 

 Neblinaea : scanty, origin in first hypodermal layer 

 Glossarion : prominent, origin in first hypodermal layer 



Subepidermal origin of cork, such as occurs in these taxa, has been found in 

 various Compositae by Douliot (1889), who did. however, record epidermal cork 

 origin in the mutisioid Barnadcsia. 



In none of the stems studied was there any indication of endodermis forma- 

 tion, either in the form of Casparian strips, such as occur in Heliantheae (Carl- 

 quist 1957d), or unevenly sclerified cells, such as occur in Barnafema. 



Laticifers. The occurrence of laticifers in Compositae belonging to tribes 

 other than Cichorieae was not generally realized until Col's (1904) demonstra- 

 tion of their occurrence in Cynareae, Vernonieae, and Arctotideae. It is of inter- 

 est that two genera included by Hoffman (1890) in Mutisieae, Berardia and 

 Warionia, were found to contain laticifers. Co] concluded on the basis of lati- 

 cifer occurrence and other characters that these two genera belonged in Cynar- 

 eae, a treatment followed by subsequent authors, such as Cronquist (1955). The 

 discovery that stems of liquid-preserved material of Gongylolepis h uachamacari 

 snbsp. neblinensis and Neblinaea promontorium contain laticiferous cells was 

 therefore of considerable interest to the writer. The nature of the laticiferous 

 structures in these two species enabled intrepretation of similar structures in 

 other genera. 



Laticiferous cells in the cortex of Gongylolepis huacJiamacari snbsp. neblinensis 

 (fig. 6),^are often somewhat larger and more rounded than neighboring cells. 

 While some laticiferous cells, by virtue of their extent, might suggest an articulat- 

 ed series from which the intervening walls had been resorbed, no such walls were 

 encountered, and the occurrence of groups of cells with intact walls suggests 

 that at least predominantly we are concerned with individual cells, some of which 

 enlarge and invade intercellular spaces. Other laticiferous cells, however, merely 

 remain rounded. That the contents of these cells was indeed latex was confirmed 

 by the milky appearance of cells e // masse, as well as under higher magnification. 

 Moreover, contents of these cells resisted safranin, a stain which is readily 

 absorbed by resinous materials. That some laticiferous cells, particularly in 

 outer portions of the cortex of G. h uachamacari subsp. neblinensis, did contain 

 resins was suggested by the presence of larger globules, which did stain deeply 

 with safranin. Such cells proved to be present not only in cortex, but also in 

 pith, leaves (fig. 21), and other parts of Gongylolepis and its allies, as well as 

 Quelchia. Identification of laticiferous cells in herbarium material was based 

 partly on their greater size, as compared to surrounding cells, and partly on 



