FILICES. (ferns.) 669 



* Stipes obscurely jointed near the base; the withered fronds falling away at the joint: 



cilia of the indusium long and inflexed over the sporangia. 

 2. W. Ilvensis, R. Brown. Frond oblong-lanceolate (2 f -6' long by 1 ' wide), 

 smoothish and green above, thickly clothed underneath as well as the stalk with 

 rusty bristle-like chaff, pinnate ; the pinnse crowded, oblong, obtuse, sessile, pin- 

 nately parted, the numerous crowded stgments oblong, obtuse, obscurely crenate, 

 almost coriaceous; the fruit-dots near the margin, somewhat confluent when 

 old. (Nephrodium rufidulum, Michx.) — Exposed rocks : common, especially 

 northward, and southward in the Alleghanies. June. (Eu.) 

 I 3. W. glabella, R. Brown. Smooth and naked throughout; frond linear 

 (2' -5' high), pinnate; pinnae roundish or ovate, the lower ones rather remote, 

 (2" -4" long), cut into 3-7 rounded or somewhat wedge-shaped lobes. — Rocks, 

 Little Ealls, New York ( Vasey) ; Willoughby Mountain, Vermont ( Wood, C. 

 C. Frost) ; and high northward. (Eu.) 



* * Stipes not jo'nted: cilia of the indusium very short and hidden by the sporangia. 

 4. W. Oregana, D. C. Eaton. Smooth; with fronds (2' -8' high, 8''- 



12'' wide) elliptical-lanceolate, pinnate, the fertile ones tallest ; pinnse triangular - 

 oblong, obtuse, pinnatifid; segments oblong or ovate, obtuse, finely toothed, 

 and in larger fronds incised ; fruit-dots near the margin ; indusium very small, 

 divided almost to the centre into a few necklace-like-jointed cilia. — Crevices of 

 rocks, south shore of Lake Superior (Robbins), and westward. 



17. DICKSONIA, L'Her. Dicksonia. (PI. 17.) 



Eruit-dots small, globular, marginal, each placed on the apex of a free vein 

 or fork ; the sporangia borne on an elevated globular receptacle, enclosed in a 

 membranaceous cup-shaped indusium which is open at the top, and on the outer 

 side partly adherent to a reflexed toothlet of the frond. (Named for James 

 Dickson, an English Cryptogamic botanist.) 



1. D. punctilobula, Kunzc. Minutely glandular and hairy (2° -3° 

 high) ; fronds ovate-lanceolate and pointed in outline, pale green, very thin, with 

 strong chaffless stalks rising from slender extensively creeping naked rootstocks, 

 mostly bipinnate ; primary pinnse lanceolate, pointed, the secondary pinnatifid 

 into oblong and obtuse cut-toothed lobes ; fruit-dots minute, each on a recurved 

 toothlet, usually one at the xxpper margin of each lobe. (D. pilosiiiscula, Willd. 

 Nephrodium punctilobulum, Michx. Dennstsedtia, Moore. Sitblbbium, J. Smith.) 

 — Moist, rather shady places : very common : pleasantly odorous. July. 



18. SCHIZJ1A, Smith. Schiz^ea. (PI. 19.) 



Sporangia large, ovoid, striate-rayed at the apex, opening by a longitudinal 

 cleft, naked, vertically sessile in a double row along the single vein of the nar- 

 row divisions of the pinnate (or radiate) fertile appendages to the slender and 

 simply linear, or (in foreign species) fan-shaped or dichotomously many-cleft 

 fronds (whence the name, from o-)(l£u>, to split). 



1. S. pusilla, Pursh. Sterile fronds linear, very slender, flattened and 

 tortuous ; the fertile ones equally slender (\ M wide), but taller (3' - 4 ; high), and 

 bearing at the top the fertile appendage, consisting of about 5 pairs of crowded 



