BOTANY. loll 



The relation of seedlings of gymnosperms to light and dark- 

 ness, A. I'.KUOKKSTKIN {II f. Prilf. Ii,>1 . (irsril., IS (J.'m). Xo. ]^, pp. 



168-lS.'i). — Detailed reports are givx'ii of investig-atioiis of more than 

 loo species of gyiuiiosperinoiis plants to ascertain the effect of light 

 and darkness upon their seedlings. The geniMal conclusions of the 

 author show that the seedlings of gynuiospernis, with the exception of 

 (x'nihjo hllolxi and EpJudra spp. , become green even in the absence of 

 light. The rapidity with whi(di the green coloration is taken on varies 

 with the temperature, the best temperature b<Mng from 15 to 25- C. 

 "^riie experiments with Cycas and Zamia showed that these ])lants even 

 ill the most favorable temperatures were unable to de\(d()[) cldoi'ophyll 

 in their seedlings in the c()m})lete al)sence of light. The author believes 

 that this genei'alization will apply to the Cycadacea'. Among many 

 of the conifei's, especially the GupressinejB, chl()ro})liyll is formed 

 under favorable temperature conditions in the al)sence of light, and 

 with the exception of Ldvii- spp. , it is^ formed not only in the cotyledons 

 but also in the hypocotyl. Experiments with Araucaiia show^ed that 

 this plant was able to produce chlorophyll in branches developed 

 while the plant was kept in darkness for several weeks, the formation 

 of chlorophyll not lieing confined to the cotyledonary leaves, as is the 

 case of the other conifers. In manj" of the Conifm-ji?, especially in 

 species of Abies and Cedrus, the embryo contains chlorophyll even in 

 the dormant seeds. In others the seedlings l)egin to turn green before 

 the seed coat is broken or shortly after the emergence of the radical. 

 Seedlings of conifers ^rowMi in the dark have shorter roots and coty- 

 ledons, but larger and thicker hypocotyls than similar plants grown in 

 the light. The cells of the hypocotyl of plants grown in darkness are 

 absolutelv longer and their diameter less than those grown in the 

 light. 



Observations on latex and its functions, .1 . Parkin {Aid}. Bat. , llf. 

 (J 900), iV^y. iJli^pp. 103-9214, 2>L !)• — Notes are given on a number of 

 observations on th(^ latex observed in rubber plants, and suggestions 

 as to its origin and functions. These observations were made during 

 an economic study of rubber and caoutchouc plants in Ceylon. The 

 coagulation of the latex is said to be brought about by the proteids 

 contained in it passing from a soluble to an insoluble form. The con- 

 ditions for this coagidation will depend upon the kind of proteid 

 present. If the proteid is a globulin or an albumin it is collected by 

 heating; if an albuminate, by neutralization. The investigations of a 

 number of different latex-bearing plants showed that in the case of 

 Ilevea Irmlliensiti the proteid is an albuminate. In Castilloa the pro- 

 teid belongs probably to the class of albumoscs, and in Ilura ci'epltans 

 the proteid seems to be largely globulin. 



Several specimens of the latex which were pure white when tirst 

 issuing from the wound rapidly darkened on exposure to the air, due 



