28 • BULLETIN 802, TJ. S. DEPAKTMEISTT OF AGRICULTURE. 



aquatic-vegetation forms and the finely divided debris which con- 

 tains seeds, pollen, spores, and chitinous and other fragments may 

 be present in varying proportions. Older and more disintegrated lay- 

 ers vary in color from dark brown to brownish black and readily 

 become granular when weathering. 



The type is derived from a diffuse stage of sedge marsh or wet 

 meadow, formed in part by rushes and other grasslike plants which 

 are usually present in many peat deposits; they are characterized 

 very frequently by the dense clumps or tussocks of Carex stricta. 

 Semiaquatic plants are abundant in the water-logged depressions 

 between the tussocks of sedges, while many herbaceous plants find 

 lodgment in such places on the drier ridges and hummocks. 



( & ) A subtype which is more characteristic in the transition series 

 to the bog group of peat materials consists similarly of a finely 

 fibrous feltlike network from rootlets and underground scale-like 

 leaves and stem portions of a variety of sedges, but usually includes 

 the thickish rootstocks of the buckbean {Menyanthes sp.) and the 

 threadlike stems of several bog plants. The material is grayish 

 brown to dark brown in color. It is not easily distinguished from 

 the peat material formed by sedges which occupy open-marsh 

 meadows, except, perhaps, for the occasional resinous and waxy 

 components from bog, heath, and other plants and in the fact that the 

 lower contact laj^ers are often poorly differentiated from the struc- 

 tureless material which formed below the floating sedge mat. Pockets 

 of water are not uncommon. 



The plant remains in the bog-sedge subtype show a rather widely 

 varying admixture of sphagnum mosses, cranberry {Vacciniuon spp.), 

 and other heath plants. Among the sedges Carex ftliformis is espe- 

 cially active on northern peat-land areas in extengling the floating 

 marginal platform of a bog meadow. 



The material of poorly disintegrated sedge peat is quite resistant 

 to cutting, plowing, and weathering. It is inclined under excessive 

 drainage to form a mull, or dust, which is peculiar also to a few other 

 types of peat material. 



Various physical and chemical data are given in Tables I and II, 

 among which are the striking differences in ether and alcohol soluble 

 extracts. 



BROWN-MOSS TYPE. 

 " Hypnum peat," "Astmoostorf." 



Brownish green to drab-colored, light, spongy, matted material, 

 often laminated and porous in appearance, derived mainly from the 

 entire plants of various species of Hj^pnum mosses or related forms 

 and containing an interbedded admixture, in varying proportions, of 

 finely fibrous rootlets from sedges, etc. 



