566 BOTANICAL GAZETTE [JUNE 
The second paper deals with 11 species, including the 6 already mentioned, 
and adding L. varium, L. Drummondii, L. fastigiatum, L. ramulosum, and L. 
Selago. Since all these species, with the exception of L. cernuum and L. Selago, 
are rather unfamiliar to European and American botanists, the writer 
describes the habit, habitat, and environmental conditions. The ecological 
treatment, based upon an immense amount of field work, is particularly inter- 
esting, since some of the species are epiphytic and some terrestrial, and, of the 
latter, some belong to wet and some to dry habitats. Young plants and pro- 
thallia are not found in localities where adult plants are abundant, but in places 
like roadside cuttings where the soil has been disturbed. It is estimated that 
15 years may elapse from the germination of the spore of L. fastigiatum to the 
fully developed prothallium; while species like L. cernuum, L. ramulosum, and 
L. laterale develop their more or less aerial and green prothallia in a single 
season. 
Since the 11 species described by TREUB, BRUCHMANN, and others showed 
5 distinct types of prothallia, it is surprising to find that among the various 
prothallia discovered by HoLtoway, no strictly new type has appeared. There 
are interesting variations, but the divergences are not sufficient to warrant 
an additional category. He believes that the Lycopodium prothallium is in a 
plastic stage of evolution, and that the various types have not been genetically 
distinct from a very remote period, but have diverged from the L. cernuum 
type, which now includes L. inundatum, L. salakense, L. laterale, and L. ramu- 
losum, and is the only one which has shown a protocorm stage in the 
embryogeny. In L. laterale and L. ramulosum a protocorm grows out into a 
rhizome-like structure, the extension consisting largely of the swollen bases of 
the successive pairs of protophylls. The stem apex, with the root rather close 
to it, appears at the end farthest from the foot. Vascular tissue develops be- 
tween the two apices, so that this region becomes the permanent axis of the 
plant. An examination of a large number of protocorms in various stages of 
development i Tey, to the conclusion that the organ may be re- 
garded as a physi tion to carry the plant over the dry season, 
and that too much phylogenetic significance should not be attached to it. 
ch an pra eliagatae would accord, more or less, with BoweEr’s ‘“‘gouty 
interlude” 
e AB op of the adult plant was studied in 11 species, and in 
8 of these the sporeling was also available. In the sporeling there is, at first, 
a single crescentic group of protoxylem embracing a single group of proto- 
phloem; later, the structure becomes diarch, triarch, tetrarch, etc., by 
the splitting of protoxylem groups, so that the pattern assumes the radial 
arrangement, the banded condition coming later. In the adult plant, the 
in L. cernuum, L. laterale, and L. Drummondii; and a parallel type in L. volu- 
bile, L. densum, L. fastigiatum, and L. scariosum. The general conclusion is 
that the various sections of the genus have not been separated from very 
