ZOOLOr.Y AND BOTANY, MICROSCOPY, ETC. 173 



anthemum^ coiled in Gistm and Fumana. Tlie radicle never l)ears 

 absorbent hairs dnring the period of germination. During the first 

 few days the hjpocotyl produces an abundance of anthocyanin (except 

 in one species of Helianthemwn) ; it also bears numerous hairs through- 

 out its length, the upper ones l)eing secretory in function. There are 

 two types of seedlings, viz. the Helianthemum type having oval dis- 

 tinctly stalked cotyledons, and the Cisius-Fumana type with cotyledons 

 which are linear, elongate, and sessile. The perennial species have 

 usually no underground stem, but Cistns umhellatus and Helianthemum 

 vidgare have well developed ones, capable of vegetative reproduction. 

 The anatomy of the root is continued as far as the cotyledons, and 

 then assumes an intermediate structure, which soon develops into 

 typical stem structure. 



Anatomical Evolution in Kalanchoe.* — A. Dauphine has studied 

 the evolution of the conducting-tissues in K. laciaiata and K. crenata, 

 and finds that development proceeds along similar lines in the root, 

 hypocotyl, and cotyledons. At first there is alternate arrangement of 

 elementary tissues, and this gradually gives place to the superposed 

 arrangement, with a generative layer and secondary formations of wood 

 and bast. The progress of evolution is more marked in the upper 

 parts than in the lower, i.e. in the hypocotyl and at the base of the 

 cotyledons the arrangement is less primitive than in the radicle ; in 

 the cotyledons themselves and in the plumule the final stages of 

 development are complete. 



Structure of Lobelia.! — L. Armand has studied the structure of 

 L. Dortmanna, especially with regard to modifications resulting from an 

 aquatic mode of life. The most interesting features are (1) the presence 

 of lactiferous vessels ; (2) perforations of the cortical cells of the root ; 

 (3) the difference in structure of the upper and lower parts of the leaf ; 

 and (4) the presence of stomata on the submerged leaves. This species 

 of Lobelia resembles the land species in having a diarch root ; in the 

 presence of hydathodes at the tips of the leaves and also of the bracts ; 

 in the stomata of the aerial stem, leaves, and l)racts ; in the lactiferous 

 vessels of the submerged stem : and in the phellogen-formations of the 

 flower-stalk and leaf-tip. It differs from them in the absence of lacti- 

 ferous vessels in the root, also in the perforated cortical cells of the 

 latter ; in the al)sence of hairs on the root, stem, and leaves, and in the 

 few stomata of both the latter organs ; in the lack of secondary tissues 

 in the root and aerial stem ; and lastly, in the large air-spaces in the 

 root, mesophyll of the leaf, and pith of the flower-stalk. These latter 

 modifications may be regarded as directly connected with the aquatic 

 mode of life. 



Development of the Vascular Structure of Dianthera americana.J 

 W. Ralph Jones, as a result of the examination of this member of the 



* Ann. Sci. Nat. Bot., xv. ^1912) pp. 153-63 (15 figs.), 

 t Rev. Gen. Bot., xxiv. (1912) pp. 465-78 (18 figs.), 

 i Bot. Gaz., liv. (1912) pp. 1-30 (4 pis.). 



