826 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the male prothallium, of the megaspore and female prothallium, and of 
the embryo of Marsilea vestita, including the development of the 
cotyledon, the stem, and the root. 
The antherozoids of Marsilea are distinguished from all others by the 
great number of coils in the spiral body, which may be as many as 13 or 
1 4 ; the cilia and the vesicle which is attached to the hinder end are 
derived from the cytoplasm. The antherid differs from that of Pilularia 
mainly in the less perfect development of the dome-shaped wall in the 
mother-cell, and in the more distinct separation of the two groups of 
antherozoid-cells. The megaspore is the most specialized found among 
the Pteridophytes. The embryo shows the closest resemblance to that 
of Pilularia , but also agrees closely with that of the Polypodiaceae. 
With regard to the systematic position of the M arsileaceac, the author 
adheres to his previous views that they ^represent the end terms of a 
series of forms whose lower members are found among the leptospor- 
angiate ferns, and probably the Polypodiaceae. Marsilea stands at the 
top and is the most specialized, with Pilularia between it and its homo- 
sporous relations. With the Salviniaceae there is little in common; 
the leaf, stem, and root grow in the same way as those of the 
Polypodiaceae, the leaves having even the peculiar circinate vernation of 
those of ferns. The development of the sporange agrees also in the 
principal details with the Polypodiaceae, and the early divisions of the 
embryo correspond almost exactly with those in that group. The first 
leaf in Marsilea is simple, like the permanent form in Pilularia ; and it 
is not till several leaves have been developed that the characteristic 
quadripartite form appears. 
Spores of Ferns.* — Dr. H. Fischer proposes a classification of fern- 
spores according to the structure of the membrane, which always consists 
of two layers, an endospore composed of cellulose and a cuticularized 
exospore, while a third outermost layer or epi spore is rarely wanting. 
The differences depend on the occasional absence of the epispore and on 
the relative thickness, colour, and structure of the other two membranes. 
Salts in Angiopteris evecta.f — MM. E. Belzung and G. Poirault 
find that the abundant sap in the petiole of this fern, when treated with 
alcohol, yields crystals of calcium malate, accompanied by monoclinic 
calcium oxalate. Sulphates and phosphates are also present in the 
soluble form, as well as tannic acid. 
Apical Growth of the Stem and Development of the Sporange of 
Botrychium.J — Mr. C. L. Holtzman finds that in Botrychium virginianum 
the stem grows by means of a distinctly recognizable three-sided pyra- 
midal cell. The sporange is first noticed as a cell of large size, byt not 
protruding beyond the other cells; and it is probable that the entire 
sporange can be referred to this single large cell, indicating a closer 
connection with the leptosporangiate group than has been generally 
supposed. The origin of the archespore is also more deeply seated than 
in the true Filices. The author derives the conclusion that the Ophio- 
glossaceaa are among the more recent families of Ferns. 
* JB. Schles. Gesell. Vaterl. Cultur, lxix. 0892) pp. 130-1. 
t Journ. de Bot. (Morot), vi. (1892) pp. 286-98 (4 figs.). 
x Bot. Gazette, xvii. (1892) pp. 214-7 (1 pi.). 
