[See No. 17]
40. SPINULOSE WOOD FERN
Aspidium spinulosum var. intermedium
Very common, usually but not always large, fronds oblong-ovate, 2–3 pinnate, lowest pinnæ unequally triangular-ovate, lobes of pinnæ thorny-toothed. In woods everywhere. P. 166.
41. BOOTT'S SHIELD FERN
From one and a half to more than three feet high. Sterile fronds smaller and simpler than the fertile, nearly or quite twice-pinnate, the lowest pinnæ triangular-ovate, upper longer and narrower, pinnules oblong-ovate, sharply thorny-toothed. In moist woods. P. 168.
42. CRESTED SHIELD FERN
Usually rather large, fronds linear-oblong or lanceolate, once pinnate with pinnatifid pinnæ, linear-oblong, fruit-dots between midvein and margin. In swamps. P. 170.
43. CLINTON'S WOOD FERN
Aspidium cristatum, var. Clintonianum
In every way larger than preceding species, fronds usually twice-pinnate, pinnæ broadest at base, fruit-dots near the midvein. In swampy woods. P. 172.
44. GOLDIE'S FERN
Large, fronds broadly ovate or the fertile ovate-oblong, once-pinnate with pinnatifid pinnæ, pinnæ broadest in the middle, fruit-dots very near the midvein. In rich woods. P. 175.