ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
555 
characters of the order and of the genera, among which the following 
may be mentioned. The order is characterised by the presence of sacs 
containing a reddish astringent kino which becomes blood-red on exposuro 
to the air. The hairs are very characteristic, being branched sympodi- 
ally. Oil-cells containing an essential oil are invariably present. The 
oil originates before the flower opens or fertilisation takes place. It is 
at first nothing bat a thickening of the integument in the region of the 
hilum, the exostome taking part in its formation. It contains an essential 
oil, a resinous substance, crystals of calcium oxalate, also in many species 
a substance intermediate between dextrin and starch. It is greedily 
devoured by birds, the ripe seeds passing uninjured through the intes- 
tinal canal. The Myristicaceae appear to be cross^-pollinated by the 
agency of insects. 
P. Physiology- 
Cl) Reproduction and Embryology. 
Orientation of the Plant-Egg.* — Under this term Prof. C. Mac- 
Millan describes the origin and development of the embryo, which he 
has followed out in the Hepaticae (j Riccia, Sphserocarpus, Marchantia , 
Anthoceros, Jungermanniaceae), and in Pteridophyta ( Equisetum , Angio- 
pteris, Isoetes, Marsilia, Pteris , Lycopodium. The following is his 
summary of the general conclusions arrived at. 
The orientation of the “ plant-egg ” is fundamentally a phenomenon 
of adaptation. The conception of a basal wall is founded upon facts of 
pliylogeny so profound that it is necessary to recognise that wall as basal 
which separates morphologically distal from morphologically proximal 
regions. The first wall formed may or may not be the basal wall. 
Three principal types of egg-orientation are recognised : — the primitive 
or bryophytic, characteristic also of Equisetum and Angiopteris ; the 
semi-inverted, characteristic of Isoetes and the leptosporangiate ferns ; 
and the inverted, characteristic of Lycopodium and Spermatophyta. The 
origin of the primitive type is in adaptation to the peripheral position 
of the archegones and to the plane of the substratum ; the origin of the 
semi-inverted type is in adaptation to derived archegonial positions and 
resistance of prothallial areas, interfering with the direct normal growth 
of the embryo ; the origin of the inverted type is in adaptation to re- 
peated archegonial displacement, and nutritive areas of prothallial areas 
adjacent. The phylogenetic sequences derived from such an ecological 
investigation of embryos do not materially differ from those derived by 
a study of pure morphology. 
Structure of the Female Organ and Apogamy in Baianophora.f 
- — Prof. M. Treub describes the female organ of Balanophora elongate, 
as originating from a papilla consisting of a single cell covered by tie 
single layer of epidermal cells. This single cell is the mother-cell of 
the embryo-sac ; the upper portion elongating into a structure resem- 
bling a style. The embryo-sac often develops from this mother-cell 
without further division ; the epiderm divides into about four layers of 
cells. The primary embryo-sac nucleus divides into two ; it is from 
the basal one of these two that the whole of the egg-apparatus is 
* Bot. Gazette, xxv. (1898) pp. 301-23 (10 figs.). 
t Ann. Jard. Bot. Buitenzorg, xv. (1898) pp. 1-25 (8 pis.). 
