ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
225 
•all the species and varieties published between 1884 and 1896, 603 in 
number. 
Dissemination of ddie Spores in Sphagnum.* — Herr S. Nawaschin 
describes the mode in which the spores escape from the sporange in 
Sphagnum, which he states to have features unknown elsewhere in the 
vegetable kingdom. The scattering of the spores is effected by the 
sudden expansion of the strongly compressed air within the sporange. 
Differences of tension in the upper parts of the wall of the sporange 
play a secondary part in the process, bringing about the detachment of 
the opercuie. Connected with this process is the remarkable abortion 
of the stomates in the wall of the sporange, there being no actual fissure 
between the guard-cells. 
Algae. 
Corallinaceae. f — Herr F. Hcydrick gives a detailed account of the 
structure and development of the Corallinaceae, especially of the 
Melobesieae. Choreonema differs from all the other genera in having no 
true attachment-disc, the rhizoids penetrating independently into the 
tissue of the host-plant. In Melobesia the entire thallus usually consists 
of a layer of rhizoids. The thallus displays no distinct differentiation 
of tissues, as is the case with the other Florideae. Vegetative propaga- 
tion takes place in the Melobesieae by growths of various kinds at 
definite spots in the basal disc ; but this is not the case with the 
Corallineae. The sexual conceptacles are always dioecious, and consist 
of cystocarps and antherids. The tetrasporanges are produced (except 
in Sporolithon ) in non-sexual conceptacles. The author regards the 
Cryptonemiaceae as the family to which the Corallinaceae arc most nearly 
allied. 
The species are arranged under nine genera, viz. : — Choreonema (1 sp.), 
Melobesia (12 sp.), Mastophora (5 sp.), Litliophyllum (12 sp.), Litho- 
thamnion (60 sp.), Sporolithon g. n. (1 sp.), besides three genera of 
Corallineae, Amphiroa, Cheilosporum , and Corallina. A number of new 
species of Melobesieae are described. Sporolithon g. n. differs from 
Lithothamnion in the tetrasporanges not being formed in true con- 
ceptacles, but in layers which permeate the thallus. 
Structure and Development of Grinnellia.l — Mr. M. A. Brannon 
has made a detailed study of the life-history of Grinnellia americana 
belonging to the Delesseriaceae. The cells, both vegetative and reproduc- 
tive, are connected with one another by protoplasmic pits, or, in the case 
of those of the procarp, by open pores. The plant is very sensitive 
to light ; mutilated plants proliferate readily. Plants may originate 
vegetatively by regeneration of the frond. Pollinoids are developed in 
enormous numbers by the abstriction of the terminal portion of the 
apical cells of the antherids. The three-celled procarp is developed from 
the supporting thallus-cell of the young cystocarp ; its apical cell 
becomes the carpogone. Fusion of the pollinoid with the trichogyne 
results in great stimulation to the thallus-cell at the base of the procarp, 
* Flora, lxxxiii. (1897) pp. 151-9 (1 pi.). 
t Ber. Deutsch. Bot. Gesell., xv. (1897) pp. 31-70 (1 pi. and 3 figs.). 
X Ann. Bot., xi. (1897) pp. 1-28 (4 pis.). 
