[ 180 ] 



CYCADACE.E. 



Sporanges on a globose axis, areolate and 

 crinite with long hairs. Veins pinnate. 



III. Metaxya. Sori globose, naked, irre- 

 gularly scattered. Indusium wanting. Spo- 

 rangia inserted on a globose axis, beset with 

 long articulated hairs. Veins pinnate. 



.B. Sori indusiate. 



IV. Hemitelia. Sorus globose, indusiate, 

 each solitary, on a pinnule. Indusium an 

 ovate, concave, torn scale, situated at the 

 lower side of the base. 



V. Hypoderris. Sori globose, indusiate, 

 regularly arranged. Indusium cup-shaped, 

 reticulated, fringed at the margin. Spo- 

 rangia inserted on an almost obsolete axis. 

 Veins anastomosing. 



VI. Cremidaria. Sori globose, indusiate, 

 regularly arranged. Indusium forming an 

 involucre, at length irregularly torn or par- 

 tite. Sporangia inserted on a globose axis. 

 Veins pinnate. 



VII. Diacalpe. Sori globose, indusiate, 

 regularly arranged. Indusium sessile, sphe- 

 rical, at first closed, at length irregularly 

 burst at the summit. Sporangia inserted on 

 a punctiform, scarcely elevated axis. 



VIII. Thyrsopteris. Sori globose, indu- 

 siate, pedunculate on stalks, which are divi- 

 sions of a bi- tri-pinnate fertile leaf. Indu- 

 sium globose-hemispherical, with an open 

 mouth; margin almost entire. Sporangia 

 inserted on a convex axis. Veins pinnate. 



IX. Woodsia. Sori globose, indusiate, 

 regularly arranged. Indusium cup-shaped, 

 open, hairy at the margin. Sporangia in- 

 serted at the bottom of the indusium, pedi- 

 cellate. Veins pinnate. 



X. Clbotium. Sori depressed-globose, in- 

 dusiate, regularly arranged. Indusium bi- 

 valve ; valves unequal, or almost equal. 

 Sporangia inserted on a convex axis. Veins 

 pinnate. 



XI. Dicksonia. Sori globose, indusiate, 

 regularly arranged. Indusium bivalve, 

 arched-semilunar on each side. Sporangia 

 inserted on a transverse, linear, crest-like 

 axis. Veins pinnate. 



XII. Deparia. Sori hemispherical, indu- 

 siate, marginal, exserted. Indusium goblet- 

 shaped, with an open mouth, torn. Spor- 

 angia stalked, on a small axis. Veins pinnate. 



XIII. Cyathea. Sori hemispherical, indu- 

 siate, regularly arranged. Indusium at first 

 closed, at length bursting in a circumscissile 

 manner, and cup-shaped. Sporanges in- 

 serted on a subglobose axis. Veins pinnate. 



XIV. Matonia. Sori globose, indusiate, 

 solitary, arising from the points of confluence 



of most of the venules, Indusium orbicu- 

 late, peltate ; the margin distinctly reflexed, 

 subglobose-hemispherical, umbonate in the 

 middle, stipitate. Sporanges about six, in- 

 serted at the base of the stalk. Veins ana- 

 stomosing. 



CYATHEA, Smith. A genus of Cya- 

 thseese (Polypodiaceous Ferns), many of 

 which are arborescent. They have a cup- 

 like indusium, whence the name. Exotic 

 (figs. 153-4). 



Fig. 153. 



Fig. 154. 



Cyathea elegans. 

 Fig. 153. Pinnule with son. Magnified 5 diameters. 

 Fig. 154. Vertical section of a sorus in a cup-like indu- 

 sium. Magnified 25 diameters. 



CYATHUS, Hall. See NIDULARIACEI. 



CYCADACE.E. A family of Gymno- 

 spermous Flowering Plants, consisting of 

 remarkable exotic trees, having somewhat 

 the aspect of Palms, but most nearly related 

 to the Coniferae. The microscopic structure 

 of the wood is analogous to that of the Co- 

 nifers, and the mode of fertilization of the 

 ovules is similar. (See GYMNOSPERMIA.) 

 Species of Cycas, Zamia, &c. are commonly 

 cultivated in botanical gardens. They offer 

 interesting subjects of microscopic investiga- 

 tion. The parenchymatous tissue, in the 

 form of pith, large medullary rays, and in 

 Cycas of concentric rings alternating with 

 those of the wood, is remarkable for the 

 quantity of starch contained in it at cer- 

 tain periods. This is extracted and used as 

 arrowroot or sago. Cycas circinalis fur- 

 nishes a kind of sago (its starch-grains are 

 represented in fig. 17. PI. 36). Dion edule 

 yields a kind of arrow-root in Mexico. Ence- 

 phalartos yields Caftre-bread at the Cape, &c. 

 The wood is composed, in Cycas and Zamia, 

 almost wholly of large dotted tubes, somewhat 

 like those of Araucaria (with many rows of 

 bordered pits) (PI. 39. fig. 20), but a medul- 

 lary sheath exists, composed of unreliable 

 spiral vessels, with tubes of varied character, 

 reticulate, annular or other fibrous forms, as 

 in the Dicotvledons, and in Zamia the dotted 



