256 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



the length of the filament, in the angle between the latter and the 

 connective, etc., correspond to stages in the development: the normal 

 mature stamen is erect, the dehiscence longitudinal, and the pollen 

 very minute and without peculiarities worth mentioning. 



On the whole, as far as is known, these stamens are very uniform 

 in their size and appearance all through the genus. They seem to 

 be of smaller dimensions and sparsely hairy on the connective in 

 C. jallax; the cells, usually narrow, are noted as broader in C. gvate- 

 malensis, where also the connectives were found to have a papillose 

 appearance on one of their faces; a cross section of the filament of 

 C. elastica is elliptic with acute edges and the connectives are here 

 larger than in the other species, with narrower cells; and finally, as 

 has already been mentioned, there occurs on these filaments, in at 

 least one species, a small, accumbent bractlet. 



COMPLEMENTAL MALE ] NFLORESCENCE. 



The small male receptacles accompanying in pairs the pistillate 

 ones, to which this name has been given, have been accurately repre- 

 sented in a considerable number of drawings of the heretofore all- 

 embracing C. elastica, beginning with the plate added to Cervantes's 

 original description and ending with the figures in Warburg's work 

 on rubber plants. Trecul h gives also a good representation of a 

 complemental inflorescence and may not have known the primary 

 one. But, strange to say, no botanist seems to have noticed the 

 variance of this inflorescence from the primary one up to the time of 

 Mr. Cook's investigations on this subject. In his bulletin on Castilla '' 

 Mr. Cook says in part : "A pair of much smaller and more fig-like 

 clusters of male flowers is often attached immediately under a cluster 

 of female flowers." As a matter of fact, these auxiliary male inflor- 

 escences are always present by the side of the female flowers in every 

 Central American species and very likely also in the South American 

 ones, although information on this point is si ill lacking. Notwith- 

 standing their reduced dimensions, they are perfect in every way, 

 differing only slightly in shape from the primary inflorescences. 

 They seem to be always geminate, and always clavate or pear-shaped, 

 except in G. lactiflua, where they are flabellate. In this species 

 they also seem to open broader than in any of the remain- 

 ing ones, but the dehiscence is always more or less slit -like, 

 except in C. costaricana, where the opening is rounded, and in 0. 

 nicoyensis, where these receptacles hardly open at all. There seem 

 to be specific differences in the length of the stipe, this being 

 very short in C. lactifiua and C. costaricana, longer and more slender 



a Warburg, O. Les plantes a caoutchouc, p. OS. (Pari?. 1902.) 



6 Ann. Sci. Nat. ser. 3. vol. S, pi. 5. (1*47.) 



c Culture of Central American rubber tree, loc. cit., p. 21. 



