PITTIER TREATMENT OF THE GENUS CASTILLA. 253 



are mostly uniform in size, shape, and other details, and yet in other 

 respects so variable in the same species, according to age, exposure, 

 etc.. that they furnish few constant specific characters. In young 

 trees they are generally larger, the petioles are often quite long, 

 attaining no less than 5 cm. in some of our specimens, and the lamina 

 is more rounded. In mature trees the petioles seem to be very short 

 (0.5 cm.) in G. ulei, short (0.8 to 1.5 cm.) in C. australis, G. 

 daguensis, G. lactiflua, C. panamensis, and G. nicoyensis, relatively 

 long (1.5 to 2 cm.) in C. fallaoa, G. costaricana, and C. elastica, and 

 longest (up to 2.5 cm.) in G. guatemalensis. Curiously enough the 

 austral species seem to have a tendency to be short-petiolate, the 

 boreal ones long-petiolate. 



The adult leaves vary from ovate and sublyrate to elliptic-lanceo- 

 late ; they furnish a good taxonomic character in the form of the 

 blade at the insertion of the petiole, this being in some species deeply 

 cordate, in others subacute or scarcely emarginate. This differential 

 peculiarity again seems to have some connection with the geographi- 

 cal distribution of the several forms, deeply cordate ones occupying 

 the northern part of the generic area, while the others are Andean, 

 with the exception of G. fallax. As to size, C. ulei has the smallest 

 leaves and G. costaricana and G. elastica the largest ones, but, except- 

 ing perhaps the first-named, there is a great variation in all the species, 

 and the dimensions given in our descriptions do not apply to the very 

 large leaves of the young trees. 



At the apex the leaf is always more or less abruptly contracted 

 into an acute point. The margin is setose-denticulate in all the 

 species, but the teeth or sinuosities hardly affect the blade itself, 

 except perhaps in G. costaricana and G. panamensis. Both faces are 

 usually densely hairy, the color of the indument varying from ashy 

 gray or silvery gray to yellowish or brownish. The texture of the 

 whole leaf is mostly coarse and the pinnate venation is very promi- 

 nent on the lower face. 



From the above details it can be seen that on the whole the leaves 

 present very few sharply defined characters and that they could 

 hardly be used alone for the identification of the several species. 

 Leaves of a species from the Atrato Valley in Colombia, which were 

 received not long ago, show, however, such decided peculiarities that 

 we must conclude to the presence of a distinct, undescribed species in 

 that region. 



THREE FORMS OF INFLORESCENCE. 



One of the generic peculiarities of Cast ilia is that all species are, as 

 Mr. Cook expresses it, a partly diepcious, that is to say, there are trees 

 that bear, at least for a single season, only male flowers, while in 



a Science, ser. '2, vol. 18. p. 437. (1903.) 



