1914) Evans,— Notes on New England Hepaticae,— XI 63 
June would probably be necessary to secure them in good condition. 
Clevea hyalina is a species of arctic and alpine regions and is known 
from many localities in Europe. In North America it has already been 
collected in Greenland, Ellesmere Land, North Lincoln, Quebec, 
British Columbia, Montana, Colorado, Idaho, Utah, Washington, 
and California. The species is fully described by Howe in his Hepa- 
ticae and Anthocerotes of California ! and by K. Müller in his Leber- 
moose Deutschlands, Oesterreichs und der Schweiz? Numerous 
interesting details may be found also in Solms-Laubach’s account of 
the “Marchantiaceae Cleveideae und ihre Verbreitung.” 3 The 
plant, however, is so different from the other Marchantiaceae known 
from New England that a few words about its most striking peculiari- 
ties may not be out of place. 
The genus Clevea belongs to the group Astroporae of Leitgeb,* so 
called because the small epidermal pores are surrounded by cells the 
radial walls of which are strongly thickened. This peculiarity is 
well marked in typical forms of C. hyalina but not in Howe's variety 
californica, known only from California, or in the rare C. Rousseliana 
(Mont.) Leitgeb, known only from Greece, Italy, Algeria, and the 
Canary Islands. Other interesting features of the Astroporae are 
- found in the method of dehiscence of the capsule and in the cells of 
the capsule-wall. The wall splits from the apex to about the middle 
into several irregular lobes with ragged edges, and no definite lines of 
dehiscence can be distinguished. "The capsule-wall is composed of a 
single layer of cells, the walls of which show numerous thickenings in 
the form of rings or half-rings. In these respects the Astroporae agree 
with most of the complex Compositae (including the genera Cono- 
cephalum, Lunularia, Marchantia, and Preissia) and differ sharply 
from the Operculatae (including the genera Asterella, Grimaldia, 
Neesiella, and Reboulia), in which the capsule opens by a more or less 
distinct circular lid and is composed of cells without annular thicken- 
ings. In addition to Clevea the Astroporae include the two genera 
Sauteria and Peltolepis, both of which have been reported from north- 
ern North America. In the structure of the thallus these three genera 
are very much alike, but good generic characters are afforded by the 
1 Mem. Torrey Club 7: 36. 1899. 
? Rabenhorst's Kryptogamen-Flora 6: 241. 1907. 
3 Bot. Zeitung 57 !; 15-37. 1899. 
* Unters. über Lebermoose 6: 49. 1881. 
