490 FERN FAMILY. 



V. 0SMU:NDA or FLOWERING FERN SUBFAMILY. 



Rather large Ferns ; the spore cases covered with reticulated 

 ridges, opening longitudinally into two valves, and with no 

 ring, or a mere vestige of a transverse ring at the back. 



89. OSMUND A. Rootstock very thick, creeping, the prowiiig end producing a crown of 

 tail showy fronds. Fertile fronds or parts of fronds contracted, pinnately compound, 

 the narrow often thread-like divisions densely covered with nearly sessile spore 

 cases. 



1. ACROSTICHUM § CHRYS6dIUM. (Greek : a row at the top, the 



application not evident.) All tropical. 



A. atireum, Linn. A large evergreen Fern, along the coast of S. Fla.; 

 the fronds .simply pinnate, coriaceous, 2°-6° long ; pinnae 4'-6' long, 

 l'-2' wide, elliptical or oblong-linear. 



2. PLATYCERIUM, STAG-HORN FERN. (Name from the Greek, 

 meaning broad horns.) Natives of Africa, Australia, etc.; cult, in 

 conservatories. 



P. alcic6rne, Gaud. Sterile fronds sessile, rather thin, flat and rounded, 

 overlapping each other ; fertile ones erect, 1° high, whitish and minutely 

 downy beneath, 2-3 times forked, with divisions about 1' wide, the top- 

 most ones fruitful. 



3. POLYPODIUM, POLYPODY. (Greek : many-footed, referring to 

 the branching rootstock.) An immense genus, found in all parts of the 

 world. 



§ 1. PoLTPODinM proper. Veins free; the folloioing native. 



P. vulg^re, Linn. Common Polypody. Rocky places N.; small, 

 simply pinnatifid, evergreen, smooth both sides, 4'-10' high, l'-.3' wide, 

 the numerous divisions oblong-linear ; fruit dots rather large. (Lessons, 

 Fig. 499.) 



P. incinum, Swartz. Shady places, Va., to 111., and S., often on trees ; 

 much like the last, but much smaller, and beneath grayish and scurfy, 

 with peltate scales ; fruit dots rather small. 



§ 2. PuLEBODiuM. Veins reticulated, with free veinlets included in the 

 larger meshes. Fruit dots in 1-3 rows between the midrib and margin, 

 commonly placed each one on the converging ends of a pair of veinlets. 



P. atireum, Linn. A large showy Fern of Fla., and cult, from West 

 Lidies ; fronds on a stout stalk, broadly ovate in outline, smooth, pale- 

 green above, glaucous beneath, pinnately parted into 5-9 or more oblong- 

 linear or lanceolate spreading divisions. 



4. GYMNOGRAMME § CEROPTERIS. (Greek : a naked line, from 

 the elongated fruit dots.) The following cult, species have free veins, 

 and the under surface of the fronds covered with a yellow or whitish 

 wax}- powder. 



* Fronds small and distinctly triangular or b-ang\dar. 



C. triangularis, Kaulf. Camfoknian Gold Fern. Frond 4'-6' long, 

 on slender and polislied stalks, broadly 3- or rather 5-angled in outline, 

 twice pinnate below, pinnate above ; pinnae oblong-lanceolate, deeply 

 pinnatifid into obtuse lobes. Smooth and green above, beneath of a ricl 



