. Our native ferns and their allies : with synoptical descriptions of the American Pteridophyta north of Mexico. Ferns. Fig. 9. Aspidiwtn (Nephrodium) rigidtiniy Swz., var. argvium. I». C. B. Enlarged segment showing indusia. (Original.) Fig. 10. A»pidium (Polystichum) munitum, Kf. Enlarged section showing indusia. (Original.) 58. Nephrolepis has roundish sori borne at the apex of the upper branch of a free vein, near the margin of the frond. The indusia are usually reniform fixed by the sinus or base and open toward the margins of the pinnae. 59. Cystopteris.—^The bladder-ferns take their pop
. Our native ferns and their allies : with synoptical descriptions of the American Pteridophyta north of Mexico. Ferns. Fig. 9. Aspidiwtn (Nephrodium) rigidtiniy Swz., var. argvium. I». C. B. Enlarged segment showing indusia. (Original.) Fig. 10. A»pidium (Polystichum) munitum, Kf. Enlarged section showing indusia. (Original.) 58. Nephrolepis has roundish sori borne at the apex of the upper branch of a free vein, near the margin of the frond. The indusia are usually reniform fixed by the sinus or base and open toward the margins of the pinnae. 59. Cystopteris.—^The bladder-ferns take their popular name from the delicate, hood-hke indusium which is attached by its broad base on the inner side of the roundish sorus and partly under it. Later this is thrown back and withers away. The veins are free and the fronds have the aspect of species of Aspidium, but are usually more delicate in texture. 60. Onoclea.—This genus contains two quite dissimilar species which, until recently, have been separated into two genera by American botanists. Both have dimorphous fronds, the margin of the contracted fertile frond being strongly revolute and con- cealing the fruit. O. Struthiopteris has necklace-shaped pinnae, crowded confluent sori, and free and simple veins. O, sensibilis has panicled berry-shaped pinnules and copiously anastomosing veins. 61. Woodsia (Fig. 11) has round- ish sori borne on the back of the veins with the indusia attached beneath the sporangia and flat and open or early bursting at the top into irregular la- ciniae or lobes. In Euwoodsia the in- dusia are flat and open from an early stage with their cleft and ciliate mar- gins concealed under the sori. In Hy- poPELTis the indusium is more con- spicuous and encloses the sporangium at first but soon bursts at the top forming several jagged lobes. 62. Dicksonia,—In this genus the small globular sorus is borne. Please note that these images are extracted from scanned page images that may have been digitally
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Keywords: ., bookauthorunderwoo, bookcentury1800, bookdecade1880, bookyear1881
