ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 665 



and a few other palms. He points out that with considerable differences 

 in the form of the embryo, maimer of germination, formation of the 

 primary root, etc., certain characters are constant. The radicle is always 

 composed of a central cylinder, a cortex distinct but not limited by an 

 endodermis, a piliferous layer, and a cap which is in close relation with 

 the root-sheath of which it forms the inner part. The piliferous 

 layers always appear late, after the external growth of the cotyledon has 

 been completed. We can recognise two phases in the germination of 

 Palms : («) a phase of preparation, in which the plantlet in course of differ- 

 entiation is carried into that medium in which it will develop ; (b) a 

 phase of development or germination properly so called. In this respect 

 the author refers to the view expressed by Karsten that the great elonga- 

 tion of the petiole of the cotyledon in certain species is an adaptation 

 which allows the young plant to find below the surface of the soil, dried 

 by a hot climate, a medium more favourable for its development. On 

 the other hand, Palms developing in a forest, that is to say a damp en- 

 vironment, develop at the surface of the soil. Thus of the two phases, 

 the length and importance of the first are a measure of the degree of 

 adaptation. 



Adventitious roots are formed at the base of the root cone. In some 

 types (admotive) one of these roots, situated in the same straight line as 

 the axis of the plumule, may play the part of the principal root, at least 

 during the first months of the life of the plant. 



Eberwein, R.— Zur Anatomie des Blattes von Borassus flabelliforniis. (Analomy 

 of the leaf of B. flabelliformis.') 



[Describes the structure of the stomata and other epidermal formations, it 

 eluding the large cells containing secretions of silica.] 



SB. K. Akad. Wiss. Wien., cxii. (1908) pp. 67-76 (1 pi.). 



Tondera, Fr. — Das Gefassbundel System der Cucurbitaceen. (The vascular 



bundle system of the Cucurbitacese.) Tom. cit., pp. 23-59 (5 pis.). 



Reproductive. 



Ovule and Seed of Cycadese.* — Marie C. Stopes has examined a 

 number of species in various stages of the ovules of Cycas, Zamia, Macro- 

 zamia, Ceratozarnia, Encephalartos, Bowenia, and Dioon. She finds that 

 the usual description of the integument as a single one, differentiated 

 into two layers, an outer fleshy and inner stony, does not hold good. In 

 all the above-mentioned genera there is also a soft inner integumentary 

 layer, which is sometimes greater in diameter than the outer fleshy layer ; 

 frequently it and the nucellus are crushed together by the growing pro- 

 thallium, but this is by no means always the case : sometimes it remains 

 fresh quite late. 



Two series of vascular bundles run in the ovule, and it is proved that 

 the inner series, frequently described as " nucellar," belong to the soft 

 inner layer of the integument. These bundles do not invariably die out 

 at the region where the nucellus becomes free from the integument, as 

 hitherto supposed, but in more than one species are found continuing in 

 the inner layer of the integument almost to the micropyle. The bundles 

 running in the outer flesh are mesarch, centripetal xylem sometimes being 



* Flora, xciii. (1904) pp. 436-82 (37 figs, in text). 



