No. 11.] THE BRYOPHYTES OF CONNECTICUT. 33 
In the latter and by far the larger group should be placed 
such species as — 
Metzgeria conjugata Leucobryum glaucum 
Plagiochila asplenioides Stereodon curvifolius 
Bazzania trilobata Thamnium alleghaniense 
Yet, however much the preceding factors affect the distribu- 
tion of the Mosses and Hepatics, the problem is eventually 
reduced to another factor, viz., the amount, nature and con- 
tinuity of the water supply. Many species grow only on dry, . 
exposed rocks, while to others the presence of free surface- 
water is essential. Some of the latter grow only in standing 
or slowly moving water, others are always found in rapidly 
flowing streams. But the majority of the Bryophytes thrive 
in an environment where they are not subjected to prolonged 
periods of drought or inundation. 
Taking the requirements with regard to water as a basis, 
Warming* recognizes four groups of plants: 
I. XerRopHytes: plants which grow on rocks, or on soil 
which contains, at least during the greater part of the year, a 
very small amount of water. 
IJ. Mersopuytes: plants adapted to soil containing a 
moderate amount of water. 
III. HypropHytes: plants which are completely or partly 
submerged, or which grow in very wet soil. 
IV. Hatopuytes: plants which are adapted to a saline 
soil. 
Considerable attention has been given to the ecological 
relationships of the higher plants, and several authors have 
attempted to classify the Bryophytes with respect to their 
habitats. Warnstorif, however, was the first to adapt 
Warming’s classification to the group. 
Among the Bryophytes there are no true halophytes. Fol- 
lowing Warming’s classification the other three groups are 
* Warming: Lehrbuch der G6kologischen Pflanzengeographie. Second German 
edition, 1902, pp. 121, 122. 
+ Warnstorf: Kryptogamenflora der Mark Brandenburg, 1: 20-25, 1903. 
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