  By S. Fred Prince. I was very much interested in Mr. Hill’s article on the cliff brakes in the January Bulletin. I lived at Madison, Wisconsin, from 1874 to 1878, and have gathered Pellaea atropurpurea many times from the sandstone cliffs, not only on Lake Mendota, but also Lake Monona and outcrops in other parts of the “Four-lake County.” I found it growing on both the Potsdam and the Madison sandstones. On the former it was only in small clumps, or isolated plants, much more sparse in growth than when on the latter, though I never found it anywhere in such dense, tangled masses as it forms in the clefts of the limestone rocks of the southwest Ozarks. I have also found Pellaea atropurpurea growing thinly, on a dark red sandstone, at Paris Springs, Missouri, not far from Springfield. I would like to add to the localities of Polypodium vulgare in Michigan. I found it, in the summer of 1910, growing in dense mats on sand dunes, south of Macatawa, Michigan. The plants were in a woodland composed principally of hemlock, with oak and a general mixture of elm, maple, hickory, etc. When you lifted a mat of the fern, the bare sand was left exposed. I thought the conditions rather peculiar. I found many ferns growing on these wooded sand hills where, at the most, there was but half an inch of soil on top of the white sand. The list includes: Adiantum pedatum; Pteris aquilina; Asplenium filix-foemina, in marshy places between the dunes; Polystichum acrostichoides, very sparingly; Nephrodium thelypteris, very luxuriant, like the lady fern, in marshy ground; Nephrodium marginale, the most common fern; Nephrodium cristatum; Nephrodium spinulosum, wherever there was a rotting chunk of wood; Onoclea sensibilis, and Onoclea struthiopteris, both very rank; Osmunda regalis and Osmunda cinnamomea, these last four in marshy spots; and Botrychium virginianum, on the sides of the dunes. I have been observing the habits of Onoclea sensibilis for many years, even raising plants from the spores to five years old; caring for other plants for years, changing conditions, and varying my experiments, until I have come to the following conclusions: When the soil is constantly and evenly moist and unusually rich, and the plant is constantly shaded, it tends to produce its fertile fronds flattened out like the sterile, with all stages to those only partly rolled up. These unrolled fertile fronds do not differ from the rolled up ones, on the same plant, except in this one particular. When a heavy screen was changed so that the plants would be in the full light and sun, the fertile fronds produced the rest of the season were as tightly rolled as usual, and it took two years of shading before these plants produced open or unrolled fertile fronds again. Varying the other conditions—moisture and nutriment, had similar results, but less marked. Champaign, Ill. |
|
