636 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
B. CRYPTOGAMIA. 
Cryptogamia Vascularia. 
Male Protliallium of Azolla.* * * § — Herr V. W. J. Bielajew describes 
the germination of the microspore of Azolla (_ filiculoides ). The processes 
show a very close resemblance to those in Salvinia, and furnish an addi- 
tional argument for dividing the Hydropterideae (Rhizocarpeae) into the 
two families of Salviniacese and Marsileaceae. 
From tbe exospore there first protrudes a tubular outgrowth, which 
pierces the spongy tissue of the massula, and which is curved as in 
Salvinia. At the base of this tubular prothallium a small lens-shaped 
ceil is separated, which is followed by a large tubular cell ; at the 
opposite upper end of the prothallium lies a rather large sterile cell, 
and between the two is a mass of fertile cells (producing antherozoids) 
arranged in two layers, each layer consisting of four cells. The cells 
of the upper layer are covered, on the ventral side of the prothallium, 
by a flat lid-cell ; and a small sterile cell also lies on the dorsal side of 
the prothallium next the lower layer. The chief difference between the 
structure of the male prothallium in Salvinia and in Azolla lies in the 
fact that in the former genus the two antherids are separated from one 
another by a large sterile cell ; while in the latter the fertile cells are 
united into a single group. 
Fructification of Marsilea.f — From an examination of the normal 
fruits of Marsilea macra , and of abnormal developments of that species 
and of M. hirsuta, Herr M. Biisgen draws the conclusion that the fructi- 
fications are homologically branches of leaves ; but that each fruit does 
not correspond to a pinna, but is equivalent to an entire sterile leaf. 
As in the isosporous Filicineae, the sporanges are developed from super- 
ficial cells of the rudiment of the fructification. 
Germination of the Megaspore of Isoetes.J — Observations on the 
earliest stages of germination of the megaspore of Isoetes echinospora by 
Dr. D. H. Campbell differ in some important points from the results 
previously recorded by Hofmeister and Farmer.§ The spores were 
fixed with absolute alcohol or chromic acid, imbedded in paraffin, and 
coloured with gentian -violet, after sections had been made with the 
microtome. The large, sharply differentiated nucleus lies at first in the 
lower posterior portion of the spore ; but, after the first stages of division, 
the new nuclei are found near its apex ; here they continue to divide until 
they amount to from 30 to 50 ; they are found exclusively in the parietal 
protoplasm, much more numerous in the apical region, and are 
entirely absent from its central and lower portion. The nuclei are 
sometimes connected by fine threads ; the cell-plates are formed between 
them, and soon become transformed into firm membranes ; the formation 
of septa commences at the apex, and advances towards the base of the 
* SB. Warschauer Naturf.-Gesell., Oct. 27, 1889. See Biol. Centralbl., x. (1890) 
p. 287. 
f Flora, lxxiii. (1890) pp. 169-82 (1 pi.). 
j Ber. Deutsch. Bot. Gesell., viii. (1890) pp. 97-100 (1 pi.). 
§ Cf. this Journal, 1889, p. 551. 
