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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[V s ol. 9, No. 3 



The tour style bundles extend from the style into the achene (fig. 105 D) where 

 they become interior bundles (fig. 105 F). The two lateral interior bundles branch 

 in the lower half of the achene (fig. 105 G) so that they are double along part of 

 their extent. The dorsiventral pair of interior bundles connect, at the achene base, 

 with adjacent exterior bundles. The lateral interior bundles, together with the 

 ovule trace, form a plexus (fig. 105 H) which separates lower down (fig. 105 I) to 

 join exterior bundles. A cylinder of bundles connects with receptacle vascular 

 tissue. The ovule trace is dichotomously branched (fig. 105 D, G). For comparison, 

 an ovule trace of S. chimantensis is shown in figure 105 J. In the ovule studied 

 of this species, the trace was dual in two places, although single at the base and 

 at the chalaza. 



Among the other species of Stenopadus for which material was available, 

 S. chimantensis, S. connellii, S. huacbamacari, S. obconicus, and S. sericeus 

 were found to have corolla vasculation like that of S. cucullatus, though median 

 bundles were entirely lacking in these species. Median bundles were found in 

 the lobes, though not in the tube, of S. colombianus corollas. Two bundles were 

 found in the styles of all of these species, and various numbers (though not 

 fewer than four) interior bundles occurred in the achenes. Ovule traces may or 

 may not be branched in these species. The frequency within the genus of various 

 vascular conditions could not be ascertained from the material available. It is 

 sufficient for the purposes of the present study, however, to note that certain 

 conditions seemingly not present in the majority of mutisioids are prominently 

 represented in Stenopadus. These features may be summarized as follows; median 

 veins are present in the corolla in addition to lateral bundles (which branch to 

 form subsidiary bundles in some species); the lateral bundles are not united in 

 the corolla, and may or may not be united in the achene; xylem of stamen traces 

 often terminates freely in the summit of the achene; at least 10 exterior bundles 

 are present in the achene; two, sometimes four, style bundles continue into the 

 achene as interior achene bundles; a dorsiventral pair of interior bundles is al- 

 ways present, and two to several lateral interior bundles are present in the achene; 

 characteristic vascular configurations occur at the base of the achene, in all 

 species forming a cylinder of independent bundles which enter receptacular tissue; 

 the ovule trace is often dichotomously branched, though it may be further ramified 

 or unbranched. 



Stifftia. 



Before comparing these vascular patterns with the remainder of Guayana 

 Mutisi^ae composing the basis for this study, a pertinent comparison can be 

 made with the flowers of Stifftia chrysantha (fig. 106), which is, like Stenopadus , 

 a South American representative of the subtribe Gochnatinae. The corollas of 

 this species (fig. 106 A), often have median veins in addition to the lateral veins; 

 lateral veins do not fuse at the corolla-lobe tips. Median veins, where present, 

 usually extend only part of the length of the corolla, terminating freely above, and 

 only infrequently continuing to the base of the corolla tube. As in the vast major- 

 ity of Compositae known, though not as in Stenopadus, adjacent laterals fuse be- 

 neath sinuses of the corolla in Stifftia chrysantha. Thus, in the corolla shown, six 

 bundles enter the achene. In addition to the six bundles in the achene continuous 

 with those of the corolla, four others are present, forming a total of ten exterior 

 bundles in the achene wall (fig. 106 C, F). Xylem of stamen traces joins with 

 that of adjacent corolline bundles in the top of the achene. In the style (fig. 

 106 B) two bundles are present. These continue into the achene as interior bundles 



