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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



(VOL. 10 



has a ' ' megaphy tic " habit of growth; that is, a single thick unbranched stem 

 bearing a rosette of leaves is formed. In the stem with secondary growth shown 

 in figure 3 } the high degree of cork development is shown, successive periderms 

 being indicated. This condition is in contrast to the relatively modest develop- 

 ment of secondary xylem. Sclereid nests are relatively infrequent in the cortex, 

 and become included in the cork during periderm formation. Bundle caps 

 occur, although intervening parenchyma never becomes sclerified to connect 

 them as it does in Stenopad/us. Tn the secondary phloem files or patches of fibers 

 are formed. The pith, which consists of thin-walled parenchyma at maturity, 

 contains occasional nests of selereids, although such nests arc fewer than in the 

 pith of Stenopadus or Stomatochaeta. Despite differences in size among species 

 (e.g. large in C. mirabilis, very small in C. rupicola) no essential differences in 

 anatomy could be detected. 



The differences among the three above genera seem related to habit features. 

 The prominence of sclerenchyma in Stenopadus may be correlated with its 

 arboreal habit. The presence of a sclerified epidermis on Stomatochaeta stems 

 is a diagnostic feature, while the limited sclerenchyma in pith and cortex, to- 

 gether with prominent cork formation, are characteristics which occur only in 

 Chimantaea. Cortical selereids have been reported for Stiff tin (Vuillemin 1884), 

 a genus which appears on other grounds to be closely related to Stenopadus. 

 Elsewhere in Compositae, the only report of cortical selereids appears to be that 

 of Quentin (1911) in Baccharis. Tt is worthy of note that nests of selereids in 

 pith and cortex of stems and peduncles are very prominent in a Hawaiian mem- 

 ber of Gochnatinae, Hesperomannia (Carlquist 1957c). 



The genus Quelchia (fig. 5), although a member of Gochnatinae on account 

 of its actinomorphic corollas, is described here in connection with Gerberinae 

 because of its stem structure. In Quelchia, as well as in Gongylolepis (fig. 4), 

 diffuse selereids are absent in cortex and pith. In both of these genera, how- 

 ever, sclerification of parenchyma cells in areas between the conspicuous bundle 

 caps occurs. Mature pith of Gongylolepis consists of lignified parenchyma cells, 

 although a few thick-walled selereids were seen in pith of G. benthamiana. Pith 

 of Quelchia conforms to the pattern seen in Gongylolepis. In all species of 

 Gongylolepis examined, a bundle cap is present on cortical leaf traces. A few 

 such fibers may also be present on the xylem pole of these traces. In Quelchia, 

 however, fibers occur only on the phloem pole of such bundles. Achnopogon and 

 Duidaea are like Quelchia, in this respect ; they have relatively few interfascicular 

 selereids, however. Tn contrast, Neblinaea possesses the same prominent cylinder 

 of sclerenchyma around the bundles as shown for Gongylolepis in figure 4. More- 

 over, occasional diffuse selereids are present in the cortex of Neblinaea. and 

 cortical leaf traces are encased in a complete cylinder of fibers, in much the same 

 manner as those of Glossarion (fio'. 7). Pith in Achnopoaon, Duidaea, and Quel- 

 chia is like that in Glossarion. Notable in the stem structure of Glossarion is the 



Fig. 4. Gongylolepis benthamiana, Maguire 33225; portion of transection of stem with 

 secondary growth, cortex :it left. Fig. 5. Quelchia cardonqe, Wurdack 565; portion of cortex 

 transection, epidermis at left. Fig. 6. Gongylolepis huachamacari subsp. rveblinensis, Maguire, 

 Wurdack 4' Bunting 37353; portion of tangential section of cortex, showing latieiferous cells 

 (shaded). Fig. 7. Glossarion rhodanthum, Maguire, Wurdack <$• Bunting 37190; portion of 

 transection of stern with little secondary growth; xylem and pith separated at right. 



