ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 775 



Although fruiting specimens have not been found, the position of the 

 genus in Cupressinese is not disputed. The genus is thus defined : — 

 Shrubs or trees with cylindrical, jointed, monopodial stems and branches, 

 the latter alternate, or whorled, often large. Leaves much reduced, gener- 

 ally triangular with a broad base and acute apex ; squamiform, appressed, 

 decussate. Internodes, variable in length, but longer in the apparently 

 annual shoots, which were more or less deciduous and functioned as 

 leaves. 



F. ramosissima ranges from bottom to top of the Lower Cretaceous 

 in the Maryland -Virginia region, to which it is thus far confined. The 

 cuticle of the type of the genus F. Hoheneggeri was described by Zeiller 

 in 1882, and in 1888 Velenovsky described the epidermal features of 

 F. bohemica. The stomata in these species consisted usually of four 

 cells, symmetrically arranged, the opening being in the form of a star. 

 According to Zeiller they indicate an affinity with Gallitris and Libocedrus, 

 and disprove Heer's contention that this genus is allied to Ephedra. 



In F. ramosissima the arrangement is similar to that of the two 

 species just mentioned. The epidermal cells are very small, roughly 

 rectangular, and with very thick walls. Their most curious feature is 

 the presence of minute, usually curved, spine-like outgrowths. The 

 curious stomatal openings which apparently characterize Frenelopsis, are 

 circular and about • 03 mm. in diameter. They are very numerous, 

 but whether they are localized on certain portions of branches which 

 perform the functions of leaves, or whether they are uniformly distributed 

 on the annual shoots, could not be determined. They consist of five or 

 six guard-cells arranged around the central stomatal opening. In their 

 more essential characters they agree with the stomata of F. Hoheneggeri 

 and F. bohemica. These features suggest strong isolation and lack of 

 humidity ; but such conditions are not suggested by other members of 

 the associated flora. These peculiar features may have been inherited 

 from triassic ancestors which acquired them when the climate was 

 extremely arid, as we know it was from physical as well as paleonto- 

 logical criteria. 



Eeproductive. 



Ovule and Embryo-sac of the Platanaceae.* — Th. Nicoloff con- 

 tributes a brief account of the development of the ovule and embryo-sac 

 of Platanus. The ovule is pendent, almost orthotropous, and the manner 

 of insertion varies. The nucellus-tissues are homogeneous at first, but 

 as the integuments are formed, differentiation takes place. The forma- 

 tion and development of the embryo-sac strongly resembles that of Spiraea 

 especially in the formation of a sort of epidermal cavity in the neigh- 

 bourhood of the micropyle and in the peculiarities of the structure of the 

 chalazal portion of the nucellus. Resemblances to Hamamdis are found 

 in the slow disappearance of the antipodal-cells, in the retardation of 

 fertilization, etc. The author considers that these facts support the 

 views of those who place the Platanaceae among the Rosiflores, on 

 account of the similarity in floral structure. 



* Comples Kendus, cliii. (1911) pp. 287-290. 



