ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
369 
£. Physiology. 
(1) Reproduction and Germination. 
Sexual Forms of Catasetum .* * * § — Mr. R. A. Rolfe points out that 
Darwin was in error in describing a hermaphrodite as well as a male 
and female form of Catasetum tridentatum , the so-called hermaphrodite 
form being really male. Lindley’s genus Myanthus must be sunk in 
Catasetum, while the same author’s Monachanthus viridis represents the 
female form of three distinct species, viz. Catasetum barbatum, eernuum , 
and macrocarpum. In this genus, while the male forms of some species 
differ widely, the female forms are remarkably alike. The author finally 
enumerates the species of Catasetum of which both sexes are known, 
sixteen in all, and subdivides the genus into four sections, of which three 
are dioecious and one hermaphrodite. 
Germination within the Pericarp in Cactacese.f — M. D. Clos 
describes the seeds of a species of Pereshia (Cactacese) from Martinique, 
which germinate normally within the pericarp ; for which purpose the 
hypocotyl is provided at its base with a small cone, which fixes itself to 
the wall of the pericarp by a network of white filaments formed of narrow 
hyaline cells. By this means nutriment is obtained for the germinating 
seed from the decaying pericarp. 
(2) Nutrition and Growth (including Movements of Fluids). 
Increase in thickness of the Coniferae.J— Herr K. Mischke has 
investigated the mode of increase in diameter of the stem, especially in 
Pinus sylvestris. The initial cambium-cell divides, and gives off cells in 
the direction of the xylem and of the phloem, which again divide once or 
twice according to the vigour of the growth ; where the growth is very 
sluggish, the cells which spring immediately from these initial cells are 
differentiated into elements of the xylem and of the phloem. Those 
which are given off towards the xylem develope into tracheids. The 
cambium forms a cylindrical layer, bounded on the inside by a xylem-, 
on the outside by a phloem-cylinder. A remarkable irregularity was 
observed in the growth of a specimen of Picea excelsa. Commencing in 
the middle of April, it attained one maximum of intensity about the 
beginning of J une, from which it rapidly sank to zero at the commence- 
ment of July; from the middle of July it again rapidly rose, and 
reached a second maximum, still higher than the first, about the middle 
of August, falling again to zero by the end of that month. 
Parasitism of Euphrasia.§ — Pursuing his investigation of the life- 
history of the Rhinanthaceae, Herr L. Koch finds Euphrasia officinalis to 
be a true and not merely a facultative parasite, and the phenomena to 
correspond in general terms with those of Bhinanthus minor. It is 
parasitic on the roots (but not on the rhizome) of grasses, and chiefly 
on the very finest roots, in which the vascular bundle has not become 
* Journ. Linn. Soc. (Bot.), xxvii. (1890) pp. 206-25 (1 pi.). 
f Comptes Rendus, cxi. (1890) pp. 954-6. 
t Bot. Centralbl., xciv. (1890) pp. 39-45, 65-71, 97-102, 137-42, 169-75 (8 figs.). 
§ Jahrb. f. Wiss. JBot. (Pringsheim), xxii. (1890) pp. 1-34 (1 pi.). Cf. this Journal, 
1889, p. 665. 
