143 



bracts. Later the stamens and the blunt, stigmatic tip of the 

 sessile ovary are protruded between the bracts to allow pollination, 

 but the fruit, even when ripe, remains half imbedded in the 

 axis. 



In Peperomia hispidula, on the contrary, we have a delicate form 

 only five or six centimeters long, with slender translucent stem and 

 roundish, thin leaves. The latter have delicate veins, the lamina 

 toward the edge consists of but two or three cells in thickness and 

 the outer cell walls are covered by only a very thin cuticle. Over 

 the upper surface of the leaf are scattered delicate hairs, which 

 are not easily wetted, and serve perhaps to keep the leaf surface 

 free from water during rainy periods. 



The structure of the inflorescence is also strikingly different 

 from that or P. verticillata. The axis of the spike is slender and 

 delicate, and the bracts are small and short-stalked. The flowers 

 are finally widely separated by the elongation of the internodes 

 of the axis, and the fruits while still young stand out from the 

 axis, each on a distinct stalk or peduncle of considerable length. 



Between the extreme types of adaptation shown by the two 

 species just described, all intermediate conditions are found. In 

 the study now being made of the genus the writer is attempting, 

 first — -to discover more exactly the relation of the structure observed 

 in the vegetable organs to the external conditions affecting each 

 species ; second — to learn whether the different types of seed 

 development, found in various species of Peperomia, are correlated 

 with peculiarities of vegetative structure and thus perhaps with 

 environmental factors. 



The species of Piper and of Hedyosmum found are being 

 studied primarily for the purpose of discovering whether the 

 seed development of any species may suggest the origin of the 

 peculiar embryo-sacs found in all the species of Peperoma hither- 

 to studied. The results thus far obtained serve to emphasize the 

 isolation of the genus Peperomia, at least as regards the mode of 

 development of its embryo-sac. 



Mr. W. D. Hoyt was at Cinchona from April 21 to July 7 

 engaged in studying and collecting the prothallia of the native 

 ferns. Interesting facts as to the structure and habitat of the pro- 

 thallia of certain species were obtained, and the spores of many 

 more species were also collected. Prothallia are now being grown 

 from these spores, which are to be used in an experimental study 

 of the problem of hybridization in ferns. 



Mr. I. F. Lewis spent the time while in Jamaica in making a study 

 of the fresh water algae of the Blue Mountain region. 



The most complete list of Jamaica algae, that of Collins* includes 

 32 species of fresh water algae. The majority of these were col- 

 lected by Prof. J. E. Humphrey of this University, from the foot- 

 hills of the Blue Mountains. In the list are 14 genera and 29 species 

 of Cyanophyceae and 3 genera and 3 species of Chlorophyceae. 



f Collins, F.S. : The Algae of Jamaica : Proc. Am. Acad. XXXVII, IQOI, pp. 

 231-270. 



