FERN FAMILY. 489 



9. Fruit dots separate or laterally confluent at or near the margin of the frond, borne 

 on the ends of the veins, or on the ends of very short side-veinlets ; the indusium 

 attached at the base or base and sides, and opening toward the margin of the 

 fruitful portion of the frond. 



21. DAVALLIA. Indusium of a single piece, flattish or often convex and shaped like half 



a goblet cut lengthwise. Exotic Ferns, mostly decompound. 



22. DICKSONIA. Indusium united by its sides with a little lobe or tooth of the frond, 



forming a minute 2-lipped cup, at first nearly or quite closed, opening as the spore 

 cases ripen. Large Ferns, native or exotic, some of the latter arborescent. 



II. CYATHEA or TREEFERN SUBFAMILY. With 

 erect and tree-like stems, often many feet high. Fruit dots 

 round, not marginal, naked, or with an involucre placed be- 

 neath the stalked spore cases, which are seated on a globose 

 or elevated receptacle, have a somewhat oblique complete ring, 

 and burst open transversely. (Lessons, Fig. 500.) 



23. CYATHEA. Fruit dots on a vein or in the forking of a vein, at first inclosed in a 



globose involucre, which opens at the top, and remains cup-shaped with an entire or 

 broken edge. 



24. ALSOPHILA. Fruit dots as in the last, but entirely naked, or with a rudimentary 



indusium consisting of a minute scale beneath the spore cases ; veins free. 



III. HYMENOPHYLLUM or FILMY FERN SUB- 

 FAMILY. These have very delicate and translucent fronds, 

 the short-pediceled spore cases growing on a short or long 

 threadlike receptacle, included in a goblet-shaped or 2-lipped 

 involucre, and furnished with a complete transverse or slightly 

 oblique ring. 



25. TKICHOMANES. Fruit dots marginal, at the end of a vein, which extends through 



the funnel-form or goblet-shaped involucre, as a thread-like receptacle bearing the 

 spore cases ; involucres sunken more or less in the frond, and of the same pellucid 

 texture. 



IV. SCHIZ^A SUBFAMILY. Mostly small Ferns, or 

 else with climbing fronds. Spore cases ovate, sessile, having 

 a complete transverse, articulated ring or cap at the apex, and 

 opening by a longitudinal slit. 



* Ferns with elegant climbing fronds, rising from slender creeping rootstocks; spore 



cases fixed by their side. 



26. LYGODIUM. Pinnse or frondlets in pairs. Spore cases covered by imbricating scale- 



like indusia in a double row on narrow lobes of the frond. 



* * Not climbing ; rootstock short ; fronds clustered; spore cases fixed by their base; 



no indusium. 



27. ANEIMIA. Spore cases on the narrow panicled branches of the lowest pair of pinnae 



of the 1-3 pinnate frond, or on separate fronds. 



28. SCHIZ^EA. Spore cases in a double row on the narrow divisions of a pinnate or rarely 



pedate special appendage to the simple and linear, or fan-shaped, and sometimes 

 many-forked frond. 



