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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
plants would probably be the best argument against his theory. 
In cultures which he made, gemmae develop eel no further than 
a vegetative body about six cells long and two to four cells wide, 
in which instance it would be impossible to tell whether the 
plants were male or female. 
The Gemmae . — The multicellular gemmae are ovoid in form, 
about .14 mm. at the greatest diameter. They are held in the 
receptacle upon hy aline stalks, one cell in thickness, and in 
some cases twice the length of the gemma. 
Throughout the period of gemma development the mucilage 
papillae have been secreting a slimy substance which is poured 
out into the flask cavity. The mature gemmae, breaking from 
their stalks, become imbedded in this viscid substance and are 
ready for expulsion from the flask. Just how this is accom- 
plished has not been fully proven. Hofmeister 9 says, “The es- 
cape of the buds is doubtless caused by the pressure which the 
numerous rapidly growing young buds necessarily exert upon 
the mucilaginous contents of their receptacle, which contents are 
thereby in constant motion toward the opening in the neck.’ 7 
Beside the pressure of the growing gemmae it is possible that the 
entrance of water into the flask causes the swelling of the muci- 
lage forcing it from the flask neck. This conclusion is supported 
by the observation of drops of the exuded mucilage standing 
at the tops of the necks, especially when the atmosphere was 
moist, or when the dew was still upon the plants. After the 
expulsion of the mucilage drop with its load of gemmae, they 
can easily be scattered. 
It is probable that insects or snails might be responsible for 
distribution of some of the gemmae through contact with these 
slime globules filled with mature brood bodies. But doubtless 
water splashing on the plant is the more efficient agency for 
gemma dispersal, as the slime dissolves quickly in water. 
These little asexual bodies grow very rapidly and produce 
.juvenile plants one to two mm. long in a few days. Their growth 
is extremely interesting and takes place while they are still 
sticking to the dorsal side of the old thallus. Leitgeb 10 was prob- 
ably referring to these new plants, which are sometimes star- 
shaped in their earlier stages, when he described the “stern- 
schuppen” of Blasia. Goebel 7 says the following in regard to 
the asexual reproduction of Blasia: “Blasia has two kinds of 
