Family 5. CYATHEACEAE 
By Wi,LIAM RaLPH Maxon? 
Mainly arboreous plants of humid tropical regions, the rhizome stout and 
woody, usually unbranched in our species, of complex fibrovascular structure, 
decumbent, ascending, or usually erect and from 1 to 15 meters or more high. 
Fronds several or numerous, borne in a crown, the stipes either articulate to the 
caudex and readily separable after maturity (in some species all falling together, 
seasonally), leaving definite scars, or imperfectly deciduous with age, the bases 
partially persistent and sheathing the thick caudex ; laminae rarely simple, in 
our species bipinnatifid to quadripinnate, mostly 1 to several meters long. Sori 
indusiate or non-indusiate, essentially globose, borne upon the veins on the 
under surface of the lamina or by suppression of the leaf-tissue at the margin, 
the receptacle thus either dorsal or terminating the vein, elevated, of varying 
form, size, and vestiture. Sporangia numerous, usually crowded, radial in 
several ranks, ovoid, dehiscing horizontally, the annulus oblique, with or 
without a definite stomium of thin-walled cells. Spores triplanate. 
Sori dorsal upon the veins, not marginal; indusium present, not formed in part of the modified 
es margin ; cells of the annulus uniform or nearly so, a definite stomium wanting. (Tribe 
“yatheae.) 
Sori indusiate, the indusium attached at the base of the receptacle. 
Indusia either (1) cyathiform, never wholly enclosing the sporangia, per- 
sistent, or (2) globose, at first wholly enclosing the sporangia, ruptur- 
ing at maturity, the divisions persistent to fugacious. 1. CvaTHEA. 
Indusia inferior, more or less semicircular in outline, often lobed, usually 
seale-like, never enclosing the sporangia. 2. HEMITELIA. 
Sori non-indusiate. 3. ALSOPHILA. 
Sori terminal upon the veins, at or near the margin; indusium at least bilobed, 
the outer portion formed of amore or less modified lobule of the leaf- 
margin; annulus with adefinite stomium of thin-walled cells. (Tribe 
Dicksonieae.) . 
Outer lip of the indusium formed of the slightly modified tissue of the leaf- 
margin. 
Plants arborescent, the caudex 1 to many meters high; ultimate segments 
of the lamina nearly symmetrical. 4. DICKSONIA. 
Plants relatively small, the rhizome usually creeping; ultimate segments 
strongly asymmetrical. 5. CULCITA. 
Outer lip of the indusium similar to the inner, formed of highly differentiated 
tissue of the leaf-margin, the indusium rigid throughout and distinctly 
bivalvate. 6. CIBOTIUM. 
1. CYATHEA Smith, Mém. Acad. Turin 5: 416. 1793. 
Sphaeropleris Bernh. Jour. Bot. Schrad. 18002: 122. 1801. 
Disphenia Presi, Tent. Pterid. 55, in part. 1836. 
Schizocaena J. Smith, in Hook. Gen. Fil. f/.2. 1838. 
Eatoniopteris Bommer, Bull. Soc. Bot. France 20: xix. 1873. 
Caudex erect in most species and often covered, at least below, with numerous adven- 
titious roots, usually paleaceous toward the summit, and commonly armed with spines. 
Stipe often similarly spiny or muricate and paleaceous, at least in the lower part; lamina 
(in our species) bipinnate to quadripinnatifid, the pinnae spreading, the secondary rachises 
variously clothed, commonly glabrescent with age and darker below; pinnules subentire 
to deeply pinnatifid or pinnate, sessile to petiolate, deciduous or not, the segments (if any) 
With the assistance of preliminary descriptions and copious notes by the late LucrEN 
Marcus UNDERWOOD. 
VoLumE 16, Part 1, 1909] 65 
