1918] CURRENT LITERATURE 567 
ancient times, but that there are rather close interrelationships in which points 
of contact and divergence may be trace 
The latest paper, issued in July, 1917, deals with methods of vegetative 
propagation, both gametophytic and sporophytic. In prothallia, vegetative 
multiplication is accomplished by decay of intermediate parts of elongated 
specimens and by the isolation of branches in irregular forms. In the sporo- 
phyte, methods are more diversified. Bulbils, like those so well known in the 
L. Selago section, are common. In L. cernuum bulbils are formed which look 
exactly like protocorms, except.that there is no foot; some of these have as 
many as 6 protophylls. Reproduction by root bidvales was found in L. cer- 
cortical cells of the root and even detached leaves may bear bulbils resembling 
the protocorms of the species. Finally, the elongated protocorms of L. laterale 
and L. ramulosum may give rise to new plants by branching and by budding. 
OLLOWAY is continuing his studies and, with abundant material and 
opportunities for observation, will doubtless give us accounts of the internal 
structures of prothallia and protocorms and especially the development of the 
vascular system of the sporeling and its transition to the vascular system of 
the adult plant. 
PsILOTALES.—With the exception of Lanc’s description of a single speci- 
men, provisionally referred to Psilotum, the gametophytes of the Psilotales 
have been entirely unknown. It was expected of Lawson that when he became 
established in the University of Sydney he would discover these gametophytes 
and give us an account, since the Psilotales are the only pteridophytes in regard 
to whose prothallia we have had no information. Two papers‘ have already 
appeared and another, dealing with the embryogeny, is in preparation. While 
Tmesipteris is epiphytic, notably on tree ferns, Lawson also found it growing 
in soil, and it was in such a situation that he found prothallia in greatest abun- 
dance. Psilotum is more xerophytic, growing in clefts in the rocks, but it also 
thrives in moist situations, even in the spray of waterfalls, and in these moist 
places most of the prothallia were found. 
In some features the gametophytes of the two genera are very similar. 
Both are subterranean and tuberous, light brown in color, and uniform in tissue, 
with no differentiation into vegetative and reproductive regions. An endo- 
phytic fungus is found in most of the cells, there being no localized fungal 
regions. Rhizoids come from all parts of the prothallium, Archegonia and 
antheridia are borne on the same individual and are not localized, but are 
scattered over all parts of the plant. The antheridia are spherical and produce 
a large number of coiled, multiciliate sperms. The archegonium consists of a 
4 Lawson, A. ANSTRUTHER, The pais of Tmesipteris tannensis. Trans. 
Roy. Soc. Edinburgh 51: 785-794. pls. 1-3. 
gametophyte aes - ae Psilotaceae. Trans. Roy. Soc. 
Edinburgh gas 93-113. pls. 1-5. 
