1957] 



ANATOMY OF GUAYANA MUTISIEAE 



449 



this genus represents an anomalous element in the subtribe Gochnatinae. An 

 entire grain of Wunderlichia mirabilis* 1 has been illustrated by Wodehouse (1929 b). 

 Although the furrows are somewhat shorter than in the genera considered here the 

 exine sculpturing (shown in optical section, Fig. 91 C) is not markedly different 

 from that of other genera in the present study. In terms of its structural charac- 

 ters, the pollen of Wunderlichia seems well v/ithin the range of the Gochnatinae 

 considered in this paper. It is of interest to note that according to the measure- 

 ments given for this species by Wodehouse, it is the only member of the Gochna- 

 tinae he investigated which matches in its dimensions the relatively large pollen 

 grains characteristic of all the Gochnatinae in the present study. 



Gongylolepis. 



As the dimensions of table 1 and the drawings of G. pedunculata (fig. 96 A, B) 

 show, most species of Gongylolepis are markedly different from all other taxa 

 studied here. With the exception of G. fruticosa, all the species of Gongylolepis 

 have larger grains, sphaeroidal in shape, with thicker exine and longer spines 

 than pollen grains of the other genera. As seen in figure 96 B, the two layers of 

 the ektexine are particularly well developed, the inner showing relatively large 

 rods (seen in a section tangential to the grain, fig. 96 C). Gongylolepis fruticosa 

 (fig. 97 A, B) has a decidedly diminished expression of these characters, but is 

 still distinguishable from grains of other taxa of this study by virtue of the sphae- 

 roidal shape and prominent spines. 



Achnopogon. 



The monotypic genus Achnopogon shows considerable similarity to Gongylo- 

 lepis in its pollen grain structure. However, the grains are not sphaeroidal, the 

 shape being best described as prolate sphaeroidal (fig. 98 A). As shown in figure 

 98 B, the thick exine, with a particularly prominent inner ektexine, is reminis- 

 cent of Gongylolepis. The rods of the inner ektexine (fig. 98 C) are smaller 

 than those of the large-grained species of Gongylolepis. The spine dimensions 

 are likewise smaller. Except for shape, pollen grains of Achnopogon are very 

 close to those of Gongylolepis fruticosa, 



Neblinaea. 



Pollen grains of the monotypic genus Neblinaea (fig. 99 A, B) have a close 

 affinity to those of Gongylolepis and Achnopogon. However, the spines are less 

 prominent than in either of these genera, the grains being less markedly spinulose. 

 As in Achnopogon, the shape of pollen grains of Neblinaea is prolate sphaeroidal. 

 The exine is only slightly thinner than that of Gongylolepis fruticosa, the two 

 layers of the ektexine being about equally prominent. 



31 The name used by Wodehouse, Kt W. tomentosa," is a nomen nudum. A comparison of 

 plants distributed by Glaziou under this name (e. g. Glaziou 2168G) with the description 

 of the type species of the genus, W. mirabilis Ried., seemingly reveals no appreciable 

 differences (see, for example, Hook. Ic. pi. 1496). Pending a new treatment of the genus, 

 these plants may be regarded as belonging to W. mirabilis. 



Explanation of Figures 96-99 



FIG. 96. Gongylolepis pedunculata; A, pollen grain; B, optical section of grain at 

 equator; C, section of inner ektexine tangential to grain surface. FIG. 97. Gongylolepis 

 fruticosa; A, pollen grain; B, optical section of grain at equator. FIG. 98. Achnopogon 

 virgatus; A, pollen grain; B, optical section of grain at equator; C, section of Inner 

 ektexine tangential to grain surface. FIG. 99. Neblinaea promontorium; A, pollen grain; 

 B, optical section of grain at equator. Figures 96C, 98C, X 1000; all others, approximately 

 X 800. Specimens represented are listed in table 1. 



