1920] 



TAYLOR— SUCCESSION OF MOSSES 



487 



elimination of such swampy regions may be very desirable. By 

 the filling up of depressions the area may be made productive 

 either as prairie or forest. The poorly drained deeper ponds are 

 probably as little to be desired from an economic standpoint, since 

 the water will not support the life of aquatic animals of commercial 

 value. Consequently any natural agency which will further the 

 change from hydrophytic to mesophytic conditions will add to the 

 number of acres of productive land reclaimed from a state of 

 total non-productivity, and also lead to better health conditions 

 for the inhabitants of the surrounding country. 



TABLE II 



Presence of moss species in associations of hydrarch succession 



Species 



Amblystegium riparium. . 



Anomodon rostratus 



Aulacomnium palustre. . . 

 Brachythecium sirulare. . 

 Campylium stellatum.. . . 

 Campy lium hispid ulum. . 

 Calliergon cordifolium . . . 

 Climacium americanum. . 

 Catharinea undulata 

 Drepanocladus aduncus. . 

 Drepanocladus fluitans.. . 

 Dicranum scoparium 

 Entodon cladorrhizans. . . 

 Leucobryum glaucum . . . 



Mnium cuspidatum 



Polytrichum commune. . . 

 Rhodobryum roseum 

 Stereodon haldanianum. . 

 Thuidium delicatulum. . . 

 Thuidium recognitum . . . 



Open water 



P 

 P 



Sedge mat 



P 

 P 

 P 

 P 

 P 



P 

 P 



Tamaracks 



P 

 P 



P 

 P 

 P 

 P 

 P 



P 

 P 

 P 

 P 

 P 

 P 

 P 

 P 

 P 



Swamp forest 



P 

 P 

 P 



P 

 P 

 P 



P 

 P 

 P 

 P 

 P 

 P 

 P 

 P 

 P 



Beech-maple 



The pannes about Miller are mostly of recent origin and are not 

 within easy reach of other habitats of aquatic mosses. This may 

 account for the fact that the few species are present. The mosses 

 found growing in all of these ponds, so far as observed, propagate 

 vegetatively only, or with very rare spore production, thus virtually 

 prohibiting their spread into distant ponds except when carried by 

 birds or other animals. As previously mentioned, these mosses must 

 be able to make a good recovery after periods of desiccation, and 

 must also be able to resist covering to some extent, as these pannes 



