. The fern allies of North America north of Mexico. Pteridophyta; Botany. Megaspore of Isoetes echinospora Flettii. appear to be trivial ones produced by tlie habitat in which they grow. Most botanists now give little atten- tion to them. According to Eaton Boottii is found in sand, and this may account for its characteristic slender leaves. Isoetes ecJiinospora mvricata is a more pronounced form. The leaves are longer, slenderer, and inclined to be spiral and the mega- spores are slightly larger, and covered with shorter, thicker, and more con- fluent spinules. In deep water the slender leave
. The fern allies of North America north of Mexico. Pteridophyta; Botany. Megaspore of Isoetes echinospora Flettii. appear to be trivial ones produced by tlie habitat in which they grow. Most botanists now give little atten- tion to them. According to Eaton Boottii is found in sand, and this may account for its characteristic slender leaves. Isoetes ecJiinospora mvricata is a more pronounced form. The leaves are longer, slenderer, and inclined to be spiral and the mega- spores are slightly larger, and covered with shorter, thicker, and more con- fluent spinules. In deep water the slender leaves are inclined to take on a spiral form. This variety is found from Nova Scotia to New Jersey. Isoetes echinospora Flettii comes from a few lakes in Washington and British Columbia, and differs from the type in having stout leaves, and the spines of the megaspores few, very short, almost wart-like. This is an extreme form and by some might be considered a distinct species. In spore char- acters it approaches the various other species of the Northwest, and except for the size of the spores might be considered a variety of Isoetes Bolanderi. A stout plant, also from northwestern America, has been named Isoetes echino- spora truncata. This has megaspores thickly covered with short truncate columns. The spores are noticeably flattened on the hemispheres contain- ing the commissures, and are not easily confused with those of other species. This form is reported from Vancouver Island to Alaska, but is as yet not common. The author would. Megaspore of Jsoetes irtntcatat. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Clute, Willard Nelson, b. 1869. New York, F. A. Stokes
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1905
