ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
81 
the outer integument only ; in Tropseolum, the testa is derived from the 
outer layers of the chalaza. The seed of Tropaeolum consists almost 
entirely of a chalazal tissue rich in protoplasm, the development of 
which is closely connected with that of the raphe and of its branches. 
Development of the Seed and of its Integument.* — Pursuing his 
investigations on this subject, M. L. Guignard now discusses the natural 
orders Borraginese, Labiatae, Compositaa, and Valerianaceas. In the 
Borragineae the facts differ in the two tribes Borrageas and Heliotropieaa. 
In the former the seminal integument is formed from the external layers 
(variable in number) of the integument of the ovule, and the endosperm 
disappears during maturation, with the exception of its superficial layer ; 
while in the latter the integument of the seed is reduced to the external 
layer of that of the ovule, and a considerable thickness of endosperm 
remains. In the Labiatse the presence or absence of endosperm corre- 
sponds to the classification into tribes. In the Compositse the integu- 
ment of the seed is developed from the single one of the ovule ; one or 
two layers derived from the endosperm are always present in the ripe 
seed. 
As a general resume , it is stated that in those Dialypetalm in which 
the ovule has a double envelope, the origin of the various parts varies, 
not only with the family, but even within the family. In all the natural 
orders here referred to, which are generally described as having exalbu- 
minous seeds, there always remains, in the ripe seed, at least one layer 
derived from the endosperm, the “ aleurone-layer ” of authors. This is 
also the case in some other “ exalbuminous ” orders, e. g. Bosacese and 
Bignoniaceae ; while in a few others, such as Limnanthese and LythraceaB, 
the mature seed is entirely destitute of endosperm. In the Geraniaceae 
the form of the embryo-sac corresponds to that which occurs in campy lo- 
tropous ovules. 
Cuticle of the Seeds of Papilionacese.t— Herr K. Schips has ex- 
amined the structure of the cuticle and of the lining of the intercellular 
spaces in the testa of the seeds of a number of species of Papilionaceae, 
and has come to somewhat different conclusions from those of Mattirolo 
and Buscalioni.f He states that the testa has a true cuticle, beneath 
which is frequently found a more or less strongly developed mucilaginous 
layer. Both these layers are distinct from the lining of the intercellular 
spaces, which is composed of three substances of different chemical and 
morphological characters. The outer of these layers is not identical 
with the cuticle ; nor are its protuberances which project into the inter- 
cellular spaces identical with the mucilaginous layer. 
To these remarks Drs. 0. Mattirolo and L. N. Buscalioni § reply, 
supporting their former conclusions by fresh arguments. The outer 
layer of the investing membrane of intercellular spaces they consider as 
allied to a cuticle in its nature, though not necessarily identical with it. 
On the question of the mucilaginous layer, the reactions obtained by 
them do not in all cases agree with those of Schips. 
* Journ. de Bot. (Morot), vii. (1893) pp. 205-14, 211-50, 282-96, 303-11 (78 figs.). 
Cf. this Journal, 1893, p. 498. 
f Ber. Deutsch. Bot. Gesell., xi. (1893) pp. 311-8. 
j Cf. this Journal, 1893, p. 62. § Malpighia, vii. (1893) pp. 305-12. 
1894 G 
