A crogynous J ungenn anniales. 
301 
is the agreement in form and size between the leaves and the 
under-leaves—a character found only in Lepidozia among the 
Cephaloziaceae. With the latter family the Ptilidiaceae agree in 
the form of the perianth, which is either cylindrical or triangular 
with one angle ventral; this sharply separates the Ptilidiaceae 
from the Lophoziaceae, in which the perianth when triangular 
has one angle dorsal. In this small but interesting and diversified 
family we find a number of features which recur in various other 
families of Acrogynae, and which are examples of parallelism, e.g., 
the development of paraphylls in Chandonanthus and Tricliocolea, 
the Frullauia-Wke pitchers of Polyotus, the “midrib” of elongated 
cells in the leaves of Herberta. 
The Scapaniaceae, which may be derived from a Lophozia- like 
type, present various features which recur in other families, e.g., 
the winged leaf Gottschea (cf. Micropterygium ) and the marsupium 
of Balantiopsis. The most marked vegetative peculiarity of this 
family is the small size of the dorsal as compared with the ventral 
lobe of the leaf. However, in some species of Scapania the two 
lobes are equal in size, or nearly so. 
The remaining four families agree with each other and differ 
from the rest of the Acrogynae in the deep division of the leaf into 
a large dorsal and a small ventral lobe, the two lobes being sharply 
folded against each other, and in the discoid form of the protonema 
and of the gemmae. In none of these four families is a mar¬ 
supium formed, and the perianth is never concrescent with the 
involucre. Each family presents strongly marked characters of 
its own, but they are probably connected with the other Acrogynae 
through Radula and Scapania. In some species of both these 
genera, the two lobes of the leaf are equal in size, and the two 
genera further agree in having a dorsiventrally flattened perianth. 
Porella agrees with Radula in general habit, but it has under¬ 
leaves, the archegonia are on special short branches, and the upper 
end of the seta is expanded to form an apophysis. Jubula is 
probably related to Porella, and from Jubula we can derive on one 
hand the genus Frullania and on the other the Lejeuneae. Pleurozia 
is a somewhat isolated genus, and it is probably more nearly related 
to the Lophozia series than to Porella and Radula, with which it is 
associated in the scheme of classification. 
