1908] CURRENT LITERATURE 421 



season in the tetrad stage, and mature early in January. Various adaptations 

 to a dry season are noted. Hygrophilous species are unable to recover from 

 desiccation, but both thallus and spores of xerophilous ones grow promptly even 

 after complete artificial desiccation. The remaining studies are concerned with 

 the germination of spores of various species, and the brief life of the green or thin- 

 walled spores, as contrasted with those of certain xerophilous species which are 

 known to be viable after two years. — C R. B. 



Florida strangling figs- — Bessey^ has studied the germination and habits of 

 the two native figs of Florida {F. aurea and F. poptdnea). In dense hammocks 

 F. aurea begins only as an epiphyte, but eventually all trace of this habit is lost; 

 while in open places it is often independent from the first. This seems to be 

 explained by the fact that the seeds germinate only in the light, and experiments 

 were performed to prove this peculiar habit. Following germination, the usual 

 gradual ^^strangling" of the host plant occurs. Roots are sent down along the 

 host plant and established in the ground, and finally by anastomosing and growth 

 they completely incase the host. Both species have two or more crops of fruit 

 ■each year, and are pollinated by different species of Blastophaga. Both kinds of 

 flowers occur in the same receptacle, and the differentiation of the flowers is not 

 so extreme as in the commercial fig. — J. M. C 



Morphology of Asimina triloba. — ^Herms' has discovered the following 

 facts in a study of Asimina triloba: the ovule passes the winter in a stage pre- 

 ceding the differentiation of the archesporial cell; the megaspore tetrad is occa- 

 sionally tetrahedral instead of linear; the embryo sac becomes remarkably 

 elongated; the polar nuclei remain in contact for three weeks or more; the 

 antipodals are very ephemeral; the first segmentation of the egg does not occur 

 for three or four weeks after fertilization; the first division of the endosp 

 nucleus is accompanied by transverse wall formation, di\iding the linear sac 

 into two equal chambers, the transverse divisions continuing until the sac contains 

 .a linear series of about twelve cells, when longitudinal division begins at the 

 antipodal end; the embr}^o is very small and little organized even in the seeC 

 J, M. C. 



Light and germination of fern spores.— LirE'° has been experimenting with 

 -the effect of light of different intensities upon the germination of fern spores. 

 The spores of Alsophila anstralis germinated about a year after collection, but the 

 .spores of other ferns germinated as soon as they were dry. Under ordinary 

 conditions the spores do not germinate in darkness; and at higher temperature 



:rm 



8 Bessey, Ernst A., The Florida strangUng figs. Rept. Mo. Bot. Garden 1908: 



r-g 



William 



Ohio 



"Naturalist 



10 LiEE, A- C, Effect of Hght upon the germination of spores and the gametophyte 



of ferns. 



09- 



