40 POLYPODIACEAE (FERN FAMILY) 



pinnatifid, linear-lanceolate (7-13 cm. long) ; the lobes oblong, obtuse, minutely 

 toothed, crowded, each bearing 3-6 pairs of oblong fruit dots, some of them 

 double. (A. thelypteroides Michx. ; Athyrium acrostichoides Diels.) Rich 

 woods, N. S. to Ga., Ala., and Minn. ; not rare. (Asia.) 



* * * fronds bipinnate ; indusia at least in part reniform or horseshoe-shaped. 



11. A. Filix-f6mina (L.) Bernh. (LADY FERN.) Fronds (4-10 dm. high) 

 ovate-oblong or broadly lanceolate, twice pinnate ; pinnae lanceolate, numerous ; 

 pinnules confluent on the secondary rhachis by a narrow margin, oblong and 

 doubly serrate, or elongated and pinnately incised with cut-toothed segments ; 

 fruit dots short, variously curved, at length confluent. (Athyrium Roth.) 

 Moist woods ; common and presenting many varying forms. July. (Cosmop.) 



11. SCOLOPENDRIUM Adans. HART'S TONGUE 



Fruit dots linear, elongated, almost at right angles to the midrib, contiguous 

 by twos, one on the upper side of one veinlet, and the next on the lower side of 

 the next superior veinlet, thus appearing to have a double indusium opening 

 along the middle. (The ancient Greek name, employed because the numerous 

 parallel lines of fruit resemble the feet of the centipede, or Scolopendra.} 



1. S. vulgare Sm. Frond oblong-lanceolate from an auricled-heart-shaped 

 base, entire or wavy-margined (12-45 cm. long, 2-6 cm. broad), bright green. 

 (Phyllitis Scolopendrium Newm.) Shaded ravines and under limestone cliffs ; 

 Woodstock, N. B. ; Grey and Bruce Cos., Ont. ; centr. N. Y. ; and Tenn. ; very 

 rare. Aug. (Mex., Eurasia.) 



12. CAMPTOS6RUS Link. WALKING LEAF 



Fruit dots oblong or linear, as in Asplenium, but irregularly scattered on 

 either side of the reticulated veins of the simple frond, those next the midrib 

 single, the outer ones inclined to approximate in pairs (so that their two indusia 

 open face to face) or to become confluent at their ends, thus forming crooked 

 lines (whence the name, from Ka^Trrfa, flexible, and o-o>/>6s, for fruit dot}. 



1. C. rhizpphyllus (L.) Link. Fronds evergreen, subcoriaceous, growing in 

 tufts, spreading or procumbent (1-3 dm. long), gradually narrowed from a 

 cordate or auricled base to a long and slender acumination, which often roots at 

 the end and forms a new plant. Shaded, especially calcareous rocks ; centr. 

 Me. to Ottawa, thence to Minn., and south w. to Kan. and Ga. The auricles 

 are sometimes greatly elongated, and even rooting ; in another form they are 

 lacking. 



13. POLYSTICHUM Roth 



Fronds tufted at the end of a stout rootstock, chiefly of firm or leathery 

 texture, evergreen ; stipes and rhachises chaffy. Sori orbicular, opening on all 

 sides of the circular peltate centrally attached indusium. (Name from TroXtf-, 

 many, and o-rtxos, row, the sori of some species being in many ranks.) 



* Fronds narrowly oblong or lanceolate, simply pinnate, the pinnae sometimes 



again cleft. 



-<- Upper (spore-bearing} pinnae of the fertile fronds much contracted. 



1. P. acrostichoides (Michx.) Schott. (CHRISTMAS FERN.) Fronds 2-5 dm. 

 long, the scaly stipe 5-15 cm. in length ; pinnae linear-lanceolate, half-halberd- 

 shaped at the slightly stalked base, serrulate with appressed bristly teeth ; the 

 smaller upper pinnae bearing two rows of sori, which in age becoming confluent 

 cover their entire lower surface. (Aspidium Sw.) Common in rocky woods. 

 Var. SCHWEINITZII (Beck) Small (Aspidium acrostichoides, var. incisum Gray) 

 is a variable form with larger fronds, toothed or pinnatifid pinnae, the fertile less 

 reduced and the sori less confluent, chiefly near the tips of the pinnae. Not rare. 



- t- Upper (spore-bearing} pinnae similar to the others. 



2. P. Lonchitis (L.) Roth. (HOLLY FERN.) Fronds linear-lanceolate, very 



