1957] 



ANATOMY OF GUAYANA MUTISIEAE 



443 



«r — £ <u oj ^ S ^ -£ -G * 



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paniculata, Maguire & Maguire 



















35392 



76 



75 



4 



2.5 



6.5 



5 



14 



15 



paruana, Maguire et al. 30236 



65 



64 



3 



2 



6 



4 



12 



12.5 



pedunculata, Cowan & Wurdack 



















31131 



79 



80 



4.5 



3 



6.5 



5.5 



15 



12 



Achnopogon 



















virgatus, Steyermark & Wurdack 



















742 



52 



46 



2 



1.5 



4 



3 



8.5 



10 



Neblinaea 



















promontorium, Maguire et al 



















37016 



50 



40 



1-2 



2 



3.5 



3 



8.5 



8.5 



Duidaea 



















pinifolia, Steyermark 58143 



55 



50 



3 



1.5 



3.5 



4 



9 



9 



tatei, Steyermark 58204 



58 



45 



1 



1.5 



3 



2.5 



7 



8.5 



Glossarion 



















rhodanthum, Maguire et al. 



















37190 



56 



52 



2 



2 



3 



3.5 



8.5 



7 



cate some relatively prominent differences among the genera and species rep- 

 resented. In the data below, the length of spines is included in all measurements 

 except endexine and inner ektexine thickness. 



The terminology in this study is derived mostly from the lucid and graphic 

 handbook of Faegri and Iversen (1050). As increasing knowledge of detailed struc- 

 ture of pollen has accumulated, new terms have been added to the literature; 

 those of Faegri and Iversen seem the most practicable at the present moment. 

 For descriptions of grain shape and spine length, the terms of Erdtman (1952) 

 have been used. 



DESCRIPTIONS 



Several features are common to all the pollen grains of the genera discussed 

 here. As the drawings of entire grains show, the three furrows on each grain are 

 long and pointed, with the edges clearly defined. Optical sections, shown to the 

 right in each plate, demonstrate the three-layered nature of the exine. The inner- 

 most of these layers, endexine (referred to by Erdtman as "nexine"), is un- 

 sculptured. Exterior to the endexine, and adherent to it, is the two-layered ekte- 

 xine. The inner ektexine (termed "endosexine" by Erdtman), which is apparently 

 continuous with the endexine and like it in staining properties, is composed of 

 rods. These rods (called "bacula" by Erdtman) may be variously shaped and 

 fused with each other, and are surrounded by a network of spaces apparently not 

 filled by any solid material. Transections of this layer (i.e., sections tangential 

 to the surface of the grain) may be seen in figures 95C, 96C, 98C, and 100C. The 

 outer ektexine differs from the inner ektexine in its staining properties and finer 



