1910] Nichols,— Notes on Connecticut Mosses 147 
not Spruce!) and Ephemerum Hampe.’ In both of these genera the 
leafy shoot is very short and consists merely of a small, bud-like cluster 
of leaves borne on an exceedingly short stem and surrounding the 
diminutive sporophyte. The whole plant in Nanomitrium is scarcely 
more than 1 mm. in height, and even in the larger forms of Ephemerum 
rarely exceeds 2 mm. From closely related forms the Ephemereae 
are distinguished by the fact that the green protonema from which 
the leafy shoots arise persists throughout the life of the plant. 
In some species, for example in E. cohaerens, the protonema becomes 
discolored with age and is not conspicuous at the time the spores 
mature; but in many cases, especially in species which, like Æ. spinu- 
losum, grow in very wet places, this structure forms a conspicuous, 
dark green mat covering the substratum about the leafy shoots. All 
of the species of Nanomitrium and Ephemerum are annuals. For the 
most part they grow in wet or moist localities, particularly in the beds 
of dried up ponds, and usually in open situations. Although some 
species occur on gravelly soil, loamy clay or humus appear to afford 
the most favorable substrata. 
As pointed out by Salmon,” Nanometrium differs from Ephemerum 
primarily in the fact that in the former genus certain cells of the cap- 
sule-wall are differentiated in such a way that the capsule possesses 
a well marked rudimentary lid. ‘The presence of a lid is indicated in 
Austin’s original description of the genus and is clearly shown in Sul- 
livant’s fig. 6 of his plate of N. Austini (Sull.) Lindb.* In Ephemerum, 
on the other hand, no traces of such a structure are apparent, but 
the capsule dehisces irregularly. In Nanomitrium, moreover, during 
the development of the sporophyte the ‘ spore-sac”’ breaks down, and 
in the mature capsule the spores are enclosed only by the thin and 
delicate outer layer of the capsule-wall. In Ephemerum, on the con- 
trary, the “spore-sac” persists, so that the ripe spores are enveloped 
by a firm, double wall of cells. Even under a dissecting microscope 
this difference in the walls of the mature capsules is easily demon- 
strated, for while in Nanomitrium the capsule is easily broken, it usually 
requires considerable picking with a needle to release the spores in 
Ephemerum. Other differences between the two genera are the 
1 Catalog. Musc. Amaz. et Andes, 2. 1867. 
2 Flora 20:285. 1837. 
3 Journ. Linn. Soc. Bot. 34:163-170. 1899. 
4 Icones Musc. Suppl. pl. 12. 1874. 
