466 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including: Cell Contents. 



Lithocysts in Ficus.* — 0. Renner has examined the cystoliths of 

 various species of the genus Ficus, and finds that by far the greater 

 number possess these bodies. They are absent in a few allied species 

 belonging to the section Eusyce, and also in an African species of 

 Urostigma. The author has classified the species according to the 

 manner of occurrence of the cystoliths. Group i. includes those species 

 in which cystoliths are absent ; group ii. includes those where the 

 upper cystoliths are enclosed in long, pointless lithocysts, while the 

 lower ones are in spherical pointed lithocysts ; group iii. comprises 

 species where the cystoliths are all enclosed in elongated or spherical 

 lithocysts having a shorter or longer point ; group iv. includes the 

 species having cystoliths in somewhat flattened, pointed lithocysts ; in 

 group v. the cystoliths are enclosed in stiff, short hairs, while in group vi. 

 they may be either in lithocysts or in the ordinary cells of the upper 

 surface. The results appear to show that the trichromatic lithocysts are 

 more important than the pointless ones, that the most extreme modifica- 

 tions occur among these latter forms, and that there is a probability that 

 they are derived partly from hairs and partly from modified trichomes. 



Structure and Development. 

 Vegetative. 



Callus-formations in Nuphar.f— II. v. Alten has studied certain 

 formations found in wounded petioles of Nwphar luteum in special relation 

 to the question of thylloses. The larvge of Ghironimus apparently make 

 their way through the stomata into the air-spaces of the upper tissues 

 and produce conditions similar to those found in Nymphsea alba. There 

 are, however, some important differences. The wounding causes the 

 otherwise fully-grown cells to send hair-like formations out of their free 

 walls, which by division ultimately form bladders. These outgrowths 

 are not found in the air-spaces immediately adjoining the wound, but 

 nearer the interior of the petiole. In the air-canals surrounding the 

 wounded parts are brownish masses of tissue which completely isolate 

 them from the healthy tissues. 



The outgrowths themselves are covered with numerous wart-like pro- 

 jections and are partially lignified, but they have no cuticle. Fine 

 octahedral crystals are found in the neighbouring cells. The outgrowths 



» Beih. Bot. Centralbl., xxv. (1910) pp. 183-200 (21 figs.). 

 t Bot. Zeit., lxviii. (1910) pp. 90-5 (2 figs.). 



