ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
549 
integument of the seed is differentiated into two layers. The develop- 
ment of the ovule into the seed presents this peculiarity in Prosopanche , 
that there is no absorption or digestion of any part of the ovule ; with 
the exception of the synergids and the antipodals, every constituent por- 
tion of the ovule is found in the mature seed. 
Seeds of the TTtriculariese.* * * § — Herr M. Merz has studied the deve- 
lopment of the seed in a number of tropical species of Uiricularia. No 
rudiment of a root could be detected in the embryo. The vascular 
bundles end in the placenta, not passing into the seed. The ordinary 
endosperm cell-division takes place in the central portion of the embryo- 
sac, while the two extremities swell up into haustoria, in which lie the 
enormously large endosperm-nuclei. The suspensor disappears after 
the abstriction of the haustorial portions of the embryo-sac. In the 
ripe seed the endosperm has entirely disappeared. There is only one 
integument. In the place of the chalaza are a number of cells which 
supply the upper swelling of the embryo-sac with nutritive material. 
The nucellus is completely absorbed during the development of the 
embryo-sac. 
The embryo of Pinguiculci vulgaris differs from that of TJtricularia in 
the absence of the constriction of the endosperm. 
Seed of Ceratonia siliqua.f — Dr. H. Marliere has studied the struc- 
ture and development of the remarkably thick membranes of the cells of 
the endosperm of the carob. He states that, at an early stage, the cell- 
wall is composed entirely of cellulose, with the exception of a very small 
quantity of pectic substance ; but that, after the secondary thickening 
has commenced, there are an outer and an inner layer of cellulose, and, 
between the two, a mucilaginous product of transformation still perme- 
ated by unchanged cellulose. When the seed is mature, this secondary 
membrane has become completely transformed into mucilage ; the cellu- 
lose can be detected only in the outermost tertiary layer. The mucilage 
is a product of the reduction of cellulose, the reticulate structure cha- 
racteristic of cell-walls being at least partially retained. In the coty- 
ledons the cell-walls are composed of cellulose, without any admixture 
of amyloid. The chemical reactions of the mucilage are given in 
detail. 
Pericarp of the B.ye.4 — Herr A. Gregory states that the well-known 
thickening of the transverse walls in the “ transverse cells ” of the peri- 
carp of the rye takes place only in the very last stage of ripening, and 
affords a practical test to distinguish ripe from unripe grains. In wheat 
and other cereals this thickening does not place. 
Assimilating Organs of Leguminosge.§ — Herr J. Eeinke has under- 
taken an exhaustive examination of the leaves and other assimilating 
organs in a large number of species belonging to the different tribes of 
Leguminosae. The ancestral type of leaf in the order was probably tri- 
foliolate, as in Trifolium ; but this became modified in a very large number 
* Flora, lxxxiv. (1897) Erganzbd., pp. G9-87 (34 figs.). 
t La Cellule, xiii. (1897) pp. 1-60 (2 pis.). 
X Beitr. z. wiss. Bot. (Fiinfstuck), ii. (1897) pp. 165-8. 
§ Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxx. (1897) pp. 1-70, 528-614 
(96 figs.). 
