660 riLiCES. (ferns.) 



into 3-5 decurrent divisions, tlioso of the fertile frond oblong or linoar-oblong, 

 entire or sparingly incised ; of the sterile ovate or obovate, crenate or incised ; 

 veins of the fertile fronds mostly only once forked. (Pteris gracilis, Uliclix. 

 AUosorus gracilis, Presl, and former ed. — Shaded calcareous rocks, Vermont 

 and Northern and Central New York, to Wisconsin and northward : rare. 

 July. — Rootstock very slender, creeping : stipes polished, brownish, darker, and 

 sparingly chaffy at the base. 



2. P. atropurptirea, Link. Smooth, except some bristly-chaffy hairs on 

 the miijribs and especially on the dark-purple and polished stalk and rhachis, C- 

 1 .5' high ; frond coriaceous, pale, once or below twice pinnate ; the divisions broadly 

 linear or oblong, or the sterile sometimes oval, chiefly entire, somewhat heart- 

 shaped or else truncate at the stalked base ; veins about twice forked. ( Pteris 

 atropurpurea, L. AUosorus atropurpureus, Kunze, and former od.) — Dry cal- 

 careous rocks : not common, but of wide range. July. — Rootstock short and 

 stout : stipes clustered. 



6. ALL0S6RUS, Bernhardi, Link. Rock-Brakh. 



Fruit-dots roundish or elongated and extending far down on the free forking 

 veins. True involucre or indusium none, the herbaceous margins of the fertile 

 segments at first reflexed and meeting at the midrib, at length opening out ilat 

 and exposing tlje confluent sporangia. — Low, with smooth, 2 - 3-pinnate fronds, 

 the fertile ones taller than the sterile, and with much narrower divisions. (Name 

 from ahXos-, various, and <rap6s, a heap.) 



1. A. aerostichoides, Sprcngcl. Stipes densely tufted, straw-colored; 

 fronds 2-3-pinnate (6'- 10' high); fertile segments stalked, linear or linear- 

 oblong (3" -5" long), the sporangia in lines extending down the veins almost 

 to the midrib, confluent when ripe and covering the under surface of the now 

 fully opened segments; sterile fronds on much shorter stipes, with ovate or 

 obovate decurrent and crenately toothed or incised segments. ( Cryptogrammo 

 aerostichoides, R. Br.) — Isle Royale, Lake Superior, thence westward and 

 northward. 



7. WOODWARDIA, Smith. Chain-Fer!?. (PI. 16.) 



Fruit-dots oblong or linear, arranged in one or more chain-like rows on trans- 

 verse anastomosing veinlets parallel and near to the midrib. Indusium fixed by 

 its outer margin to the fruitful veinlet, free and opening on the side next the 

 midrib. Veins more or less reticulated, free towards the margin of the frond. 

 — Large Ferns, with pinnatifld or pinnate fronds. (Named for Thomas J. 

 Woodioard, an English botanist.) 



§1. ANCHfSTEA, Presl. Sterile and fertile fronds alike: veins forming only one 

 roio of meshes [areoles). 

 1. W. Virginioa, Smith. Fronds (2° -3° high) pinnate, with numerous 

 lanceolate pinnatifld pinnae ; segments oblong ; veins foiining a row of narrow 

 areoles along the midrib both of the pinnae and of the lobes, the outer veinlets 

 free ; fruit-dots oblong, one to each areole, confluent when ripe. — Wet swamps, 

 Maine to Virginia, and southward. July. 



