. Our native ferns and their allies : with synoptical descriptions of the American Pteridophyta north of Mexico. Ferns. And Their Allies 31 The outer layer {exospore) consists chiefly of cellulose; the inner layer [endospore] contains some albuminous matter in addition, while the cell contents consist chiefly of a thin, colorless, jelly- like substance known as protoplasm, with grains of chlorophyll (the green coloring matter of plants), starch and oil. The exo- spore may be smooth or roughened by points, granules, warts or prickles. The shape varies with different species yet all are rounded,
. Our native ferns and their allies : with synoptical descriptions of the American Pteridophyta north of Mexico. Ferns. And Their Allies 31 The outer layer {exospore) consists chiefly of cellulose; the inner layer [endospore] contains some albuminous matter in addition, while the cell contents consist chiefly of a thin, colorless, jelly- like substance known as protoplasm, with grains of chlorophyll (the green coloring matter of plants), starch and oil. The exo- spore may be smooth or roughened by points, granules, warts or prickles. The shape varies with different species yet all are rounded, and most are oblong or at least longer than broad. All are microscopic and many are of such a shape that they do not appear unifomr, owing to the various directions from which we view them. (Fig. 14-21).. Fig. 14-21. Spores, highly magnified. Cryptogramme acrostichoides, R. Br., Lygo- diwm palmatumy Swz., Cystopteria fragilis, Bernh., Schizsea pusilla, Pursh. Acroatichum aureum^ L., Polypodium Califomicum, Kf,, Gymnogramme triangidaris, Kf., Notholsena Candida^ Hook. (Original.) 69. The number of spores produced by a single fern is in- credible. Lindley calculated that a single frond of Scolopendrium produced about 80 sori, with an average of 4500 sporangia in each sorus, and each sporangium containing 50 spores, making a total of 18,000,000 spores. The copious green spores of Osmunda cin- namomea or the pale yellow, powdery spores of a well developed specimen of Botrychium Virginianutn must far exceed this com- 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 Underwood, Lucien Marcus, 1853-1907; Underwood, Lucien Marcus, 1853-1907. Our native ferns and how to study them. Bloomington, Ill. Leader Pub. Co.
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