1957] 



ANATOMY OF GUAYANA MUTISIEAE 



457 



A somewhat more complex situation is represented by Stenopadus kunhardtii 

 (fig. 103). In the corolla (fig. 103 A), lateral and median veins are present, as in 

 5. campestris. In addition, subsidiary veins branch from the laterals at various 

 points between the level of departure of stamen traces and the bases of the 

 sinuses. These subsidiary veins occupy a position between the lateral veins 

 and the margins of each lobe, and extend for various distances into the distal 

 portion of the lobes, where they terminate freely. This pattern of corolla venation 

 has been found elsewhere in the Compositae only in Fitcbia mangarevensis 

 (Carlquist 1957 a, b). At the base of the corolla of S. kunhardtii, the laterals con- 

 tinue into the achene, without fusion of adjacent laterals (fig. 103 C). Likewise, 

 the five median veins of the corolla extend into the achene independently. The 

 xylem of stamen traces terminates freely in the achene top. In the achene, more 

 than the fifteen bundles continuous with those of the corolla are found. These 

 additional exterior bundles (fig. 103 C)are branches of the fifteen corolla bundles. 

 As in S. campestris, the style of S. kunhardtii contains two bundles (fig. 103 B) 

 which connect with a dors iventr ally arranged pair of bundles in the achene (fig. 

 103 D). These connect with adjacent exterior bundles in the achene base (see 

 also fig. 103 I, J). Numerous other interior bundles are present in the achene. 

 These terminate freely above, but connect in a plexus with the ovule trace below, 

 this plexus then separating to join several of the exterior bundles in the achene 

 base (fig. 103 I)- The ovule trace (seen also in fig. 103 G) is branched several 

 times. At the base of the achene, a cylinder of bundles enters the receptacle. 



In Stenopadus stipitatus (fig. 104), as in S. kunhardtii, there is a remarkably 

 complex corolla vasculation(fig. 104 A). Because of the various ways in which 

 the bundles unite, the designation of median, lateral, and subsidiary bundles can- 

 not be made in S. stipitatus. The basic pattern of five bundles in each corolla- 

 lobe seems evident, however. All bundles of the corolla-lobes terminate freely 

 above. At the corolla base, as in S. kunhardtii, the bundles in the corolla tube 

 pass into the achene without union of adjacent laterals (fig. 104 C). Xylem of most 

 stamen traces terminates freely in the achene summit without coming in contact 

 with that of the corolline bundles. As in the two above species, two style bundles 

 are present (fig. 104 B, C, E). These are connected with a dorsiventral pair of 

 interior achene bundles (fig. 104 D). In addition, a lateral pair of interior bundles 

 is present; all four interior bundles, together with the ovule trace, form a vascular 

 plexus at the achene base (fig. 104 H). This separates, further down, to form 

 strands joining the exterior bundles (fig. 104 I). The ovule trace is dichotomous 

 on the adaxial face of the ovule (fig. 104 G). As in the above species, a cylinder 

 of bundles enters receptacular tissue. 



In Stenopadus cucullatus (fig. 105), a much simpler corolla venation is found 

 (fig. 105 A). Lateral bundles, which fuse at the apex of each corolla lobe, are 

 present, but median veins are only occasionally present in lobes, and do not 

 extend into the tubular portion of the corolla. As in S. kunhardtii and S. stipitatus, 

 the lateral bundles enter the achene, without union of adjacent laterals, and 

 form a series of external bundles (fig. 105 C). In the style (fig. 105 B), a pair of 

 larger dorsiventrally arranged bundles is present; in addition, a lateral pair of 

 small bundles extends part way up the style, fusing with the larger bundles. 



Explanation of Figure 103 



FIG. 103. Stenopadus kunhardtii (Maguire & Politi 27896), portions of flower drawn to 

 show venation. A, corolla; B, style; C, achene, showing exterior bundles; D, achene, 

 showing interior bundles; E-J, successive sections of corolla base and achenes at level 

 indicated by (E) through (J) above. A, B, X 4-5; C-J, X 9. 



