1904] JOHNSON—MONOCLEA . 187 
but failed to recognize the full importance of the differences between 
the involucre, calyptra, and sporogonium of M. crispata and those of 
the other forms included in the genus by HooKER and Taytor, and 
apparently based the division of the genus chiefly on the columella. 
GOTTSCHE (’58) studied material of Monoclea from Chili. From 
this he described the gross and minute structure of the vegetative 
thallus, noting the presence of two types of (non-tuberculate) rhizoids 
and the occurrence of fungus hyphae in certain cells of the thallus. 
The involucre he thought completely closed at first. He also described 
the structure of the mature sporogonium, from the foot to the capsule, 
with its one-layered wall, unicellular elaters, and roughened spores. 
On the basis of these observations GorrscHE clearly distinguishes 
M. Forsteri from the species of Dendroceros with which it had been 
associated by Hooker, Taytor, and NEEs, and seems to find in it 
close resemblances to Pellia and Blasia, with which he frequently 
compares it. He also remarks on the outward likeness to Marchantia 
which had been noted earlier by Hooker (’20, p. 176). 
Nine years later still GorrscHE (’67) discovered the elevated, 
oval male receptacle on plants of Monoclea from Mexico. 
The next important worker on the genus was LEITGEB (’77), who 
confirmed the work of Gottsche on the structure of the thallus, calyptra 
and capsule, and insisted on the similarity in structure and branching 
of the thallus with that of Pellia and Symphyogyna, rather than with 
that of the dichotomous, areolate Marchantiaceae. He described 
the slender, thick-walled rhizoids, found by GoTTSscHE (’58), as gener- 
ally distributed over the under side of the thallus, and as lying parallel 
to it, while the larger, thin-walled ones are, as GOTTSCHE showed, 
confined to the median portion of the thallus and stand out perpen- 
dicular to the latter. LxrrcEs found that the involucre arises as a 
depression in the tip of the thallus, being closely like that of Pellia 
in origin and structure. He also discovered that the involucre is 
independent in its development of that of the sporogonium, and even 
of fertilization. No young archegonia or embryos were found. The 
mature archegonia occur in groups of eight or ten, have a large venter, 
and a long twisted neck. The capsule he thinks imperfectly four- 
valved. From these facts LeE1TGEB concludes that Monoclea is more 
closely related to Pellia than to any of the Marchantiaceae. 
