EXPLANATION OF PLATES XIV-XVI.

The photographs and photomicrographs were made by the author, except fig. 3 of plate XIV which was made from a print kindly loaned by Mr. C. G. LLOYD.

PLATE XIV.

FIG. 1. Plants collected at Ithaca on very rotten wood. a, Clavaria form; b, Spathularia form; c, abnormal form; d, young individual; real size.

FIG. 2. Pure culture in test tubes, parentage from a and b of fig. 1; real size. FIG. 3. Hypocrea Lloydii Bresadola, from leaf mold; note that one-half of the stem was developed underneath the leaves and leaf mold, which makes the stem long; real size.

PLATE XV.

Photomicrographs from plants collected at Ithaca. In figs. 4, 5 the plateholder was 36cm from the object, and in fig. 6, the plate-holder was 48cm from the object.

FIG. 4 with Zeiss ocular 4, obj. 16mm.

FIG. 5 with ocular 4, obj. 3mm.

FIG. 6 with ocular 18, obj. 3mm. Note the chain of 16 segments of the eight spores from a single ascus, beginning at apex of series at left, the segments alternate, globose or cuboidal, and oblong.

PLATE XVI.

Photomicrographs from type specimen of Hypocrea Lloydii Bresadola. In figs. 7, 8 the plate-holder was 36cm from the object, and in fig. 9 the plate-holder was 48cm from the object.

FIG. 7 with ocular 4, obj. 16mm.

FIG. 8 with ocular 4, obj. 3mm

FIG. 9 with ocular 18, obj. 3mm. Note form of the sixteen segments in the chain of 8 spores from one ascus, apex of series at left.

THE BOGS AND BOG FLORA OF THE HURON RIVER

VALLEY.

EDGAR NELSON TRANSEAU.

(WITH SIXTEEN FIGURES)
[Continued from p. 375.]

THE BOG AS A HABITAT FOR PLANTS.

WHEN We consider the bog as a habitat for plants, there is at once brought to mind the marked contrast between its characteristics and those of the other plant habitats of its vicinity. In both its atmospheric and edaphic conditions it is unique. The various factors entering into the plant environment will be discussed as physical, chemical, and biotic agents.

A. PHYSICAL FACTORS.5.-1. Wind.-Because of the fact that so large a number of our bogs lie in depressions surrounded by hills, the influence of the wind is somewhat lessened. It is only in the case of the larger basins that its effects become marked. It has been noted by several students of bogs (41, 5, p. 37; 59, 47) that in the region of prevailing westerly winds the greatest development of bog areas and peat deposits occurs on the western sides of lake basins. Where the deposition has taken place in a large lake basin, which is now only partially filled, we commonly find open water occurring toward the eastern side. The peat deposits at Portage, Parks, and West Lakes in the vicinity of Ann Arbor are massed on the western shores, while the eastern margins exhibit an ordinary lake beach. At the bogs north of Delhi, although nine-tenths of the original basin has been filled, the two small lakes are near the eastern margin. The facts noted in this region all favor the idea of the bog plants being unable to gain a foothold on the eastern side in the presence of wave action. The shoreward thrust of the ice is of importance at times in this connection.

Farther north in Michigan the wind frequently shows its extreme effect in these bog areas in the presence of "windfalls." Owing to the character of the substratum, such areas are more readily affected