ANDREAEACEAE, 347 
treated as independent species are really forms only of some of the 
species with plants of the subantarectie region, especially of Fuegia, 
where a considerable number of new species have been described by 
Dusén and others, without apparently a close comparison being made 
with the New Zealand forms. 
The petrophila group, as it may be called, presents great per- 
plexities. As in other genera, characters which have little value have 
been relied on in the past to separate species. — this is the 
case with the papillosity of the leaves, which may exhibit a great 
range of development on a single stem, much more on a single tuft. 
To a less extent this applies to the character drawn from the toothing 
or otherwise of the basal margin of the leaves; this is no doubt in 
some species a useful and constant character ; but in A. acuminata 
at es the margin may be either toothed or entire. 
Andreaea os been divided into two, and later into three sub- 
genera. Hook. f. & Wils. separated Acroschisma from the rest of 
the genus aor es on the ground of the valves of the capsule oceasion- 
ally numbering more than four, be to eight (each valve occasionally 
having a secondary fissure), a also on the character that the 
valves do not exted to the bate ee the capsule, the greater part of 
which bape undivide 
ecently Lindberg has employed another character to 
divide the remaining species, viz., Eu-andreaea, where the perichactial 
“— are large, convolute, much differentiated from the stem leaves ; 
Chasm heals in which they are very little differentiated, not 
saat and convolute. These three Uae ag form the basis of 
Brotherus’s classification in the ‘‘ Musci,’’ and of Roth’s in the 
Aussereuropaisch. Laubmoose, vol. 1. 
I have already (Smithsonian Miscell. renee f1918] 69: 2, p. 9), 
called attention to a structural peculiarity in an Andreaea from Mt. 
Kenia, which suggests the possibility that the principal character 
on which Acroschisma is founded is of less a than ~ authors 
supposed. This conclusion is supported, indeed confirmed, by exami- 
nation of another group of species. C. Mueller vier i 8) writes 
of A. subenervis H. f. & W. from the Andes of New Granada, that 
from the form of the capsule it appears to be nearest to A. Wilsoni 
(i.e, Aecroschisma). Examination of Wilson’s specimens of A. 
subenervis at the British Museum entirely confirms this; the capsules 
are, and are sketched by Wilson entirely of this character, the basal 
portion—perhaps two-thirds of the capsule—being entirely undivided, 
ce this is not the ease in the single capsule of the Quito specimen. 
Now in the New Zealand A. aquatica and A. mitida, both of which 
are G say the least closely allied to A. subenervis, the capsule is 
perfectly normal for Andreaea, ie., the valves reach to the base 
It appears best, therefore, to retain ‘the New Zealand species under 
Chasmoealyx, leaving Acroschisma provisionally a monotypic sub- 
genus based upon be number of valves as well as upon the degree 
of fission of the capsule. 
The followi my is a tentative Key to the species, but I must 
frankly admit that it is probable that some of the separating char- 
