206 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Epipogium storaates are wanting on the stem. The vascular bundles are 
usually of simple structure. The intercellular system and strengthening 
tissues are but feebly developed. 
All holosaprophytes have small seeds with a rudimentary unseg- 
mented embrj^o; the ovules frequently do not develope into fertile 
seeds, showing that the structure is the result of degradation. The 
ovules of Voyria (Gentianacese) are destitute of integument, resembling 
those of BalanopJiora. The seeds of Sciaphila contain endosperm, and 
the author regards the natural order Triuriaceae as nearly allied to 
Alismaceae. 
Graminese and Cyperacese.*— After describing the inflorescence of 
the Brazilian genus of grasses Streptochseta, Dr. L. Celakovsky dis- 
cusses the phylogenetic connection of the orders Gramineae and 
Cyperaceae, regarding both as descended, in different lines, from the 
Juncaceae, the former having departed the more widely from the an- 
cestral form. The reduction of the number of ovules to one, and the 
origin of this from the base of the ovary, is a phylogenetic advance 
common to the two orders ; the usual coalescence of the ovule with the 
wall of the ovary, and the formation of the scutellum in the grasses, are 
further steps in advance not found in the sedges. The position of 
the embryo in the Cyperaceae, surrounded by the endosperm, is also 
more archaic than the lateral position in the Gramineae. The same is 
also the case with the 2-3-car2)ellary pistil of the Cyperaceae, contrasted 
with its 1- or 2-carpellary structure in the Gramineae. 
With regard to the inflorescence, that of grasses is usually diplocaulic 
(biaxial), while that of the Cyperaceae is frequently haplocaulic (uni- 
axial). The inflorescence of the tribe Cariceae of the order Cyperaceae 
the author states to be indefinite ; and they are therefore more nearly 
allied to the Scirpoideae than to the Caricoideae, under which they are 
usually placed. 
B. Physiologry. 
(1) Reproduction and Germination. 
Physiology of Reproduction. t — Dr. G. Klebs brings forward evi- 
dence in favour of the view that the mode of reproduction in the lower 
organisms, whether sexual or non-sexual, is largely dependent on external 
conditions. The experiments here described were made entirely on 
Hydrodictyon utriculatmi, in which the two modes of reproduction are 
well known — non-sexual by means of zoospores, and sexual by means of 
motile gametes which conjugate to form a zygote ; the cycle being 
generally closed by the production of a sexual succeeding a number of 
non-sexual generations. 
Dr. Klebs finds that, by cultivating this alga in a 0*5-1 per cent, 
nutrient solution, composed of 1 part magnesium sulphate, 1 part potas- 
sium phosphate, 1 part potassium nitrate, and 4 parts calcium nitrate, and 
then bringing it into fresh water, the formation of zoospores is greatly 
promoted ; but that it is in all cases absolutely dependent on light, 
which must, at least for a time, act upon the culture. It is, however, 
* SB. K. Bohm. Gesell. Wiss., 1889, pp. 14-12 (1 pi.), and 9-118 (1 pi.), 
t Biol. Centralbl., ix. (1889) pp. G09-17. 
