. Our native ferns and how to study them; with synoptical descriptions of the North American species. Ferns. Fructification. 33. the midvein. In some species part of the indusia are double. The veins are free in all our species. In Euasplenium the sori are straight or slightly curved; in Athyriom they are often curved, even horseshoe shaped and frequently cross to the outer side of the fruiting vein. 49. Scolopendrium (Fig. 9), bears the linear sori in pairs, one from the upper side of a veinlet and its mate from the lower side of the next. The indusia are attached by their edges to the veins,
. Our native ferns and how to study them; with synoptical descriptions of the North American species. Ferns. Fructification. 33. the midvein. In some species part of the indusia are double. The veins are free in all our species. In Euasplenium the sori are straight or slightly curved; in Athyriom they are often curved, even horseshoe shaped and frequently cross to the outer side of the fruiting vein. 49. Scolopendrium (Fig. 9), bears the linear sori in pairs, one from the upper side of a veinlet and its mate from the lower side of the next. The indusia are attached by their edges to the veins, and folding toward each other appear like a double indusium covering a single sorus. The veins extend nearly at right-angles to the mid- vein, are free and usually forked. so. Camptosorusl The walk- , r 1 11 1- . Fig. 9. Scolopendrium vulgare, mg-leaf has oblong or hnear m- g^ section of frond showing vena- dusiate sori, which are irregularly tion and fructiiication. (Original.) scattered and' borne partly on veins parallel to the midvein, and partly on those that are oblique. Those near the midvein are sin- gle, those toward the margin are often approximate in pairs and often form crooked lines. The veins are everywhere copiously reticulated. 51. Phegopteris.—In this genus the sori are round and naked as in Polypodium with which this genus is sometimes united. The sporangia spring from the back of the veins instead of the apex as in the latter genus and the veins are free. 52. Aspidium is largely represented in our limits by two well marked sections which are sometimes regarded as distinct genera, and a third section with characters less distinct containing a sin- gle species. In all the sori are roundish and borne on the back of the veins or rarely at their apex. In Nephrodium the indu sium is cordato-reniform or orbicular with a narrow sinus. This at first covers the sorus and is attached by its margin, but later busts away at the margin but remains attached at the sinus.
Size: 1587px × 1574px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorunderwoo, bookcentury1800, bookdecade1880, bookyear1881
