XX. CEKATOPTERIS. 
41 
2. H. coRDATA, Uoxhurgh. — A beautiful low-growing evergreen stove Fern, from the East Indies. Fronds 
simple, cordate, hairy, especially on the raehis and margin; the sterile ones deep green, four to six inches long, 
roundish at the apex ; the fertile erect, cordate-sagittate or sub-trilobate and triangular, six or eight inches high. 
Stipes ebeneous. Fronds terminal, adherent to a small tufted rhizome. This Fern was raised at Kew, in 1852, 
from spores, but has not yet produced fructification. 
XX. CERATOPTERIS, Bromjnlart. 
Soyi linear, continuous, parallel, superficial, produced on the lengthened transverse sides of the 
venules, and concealed by the reflexed margin of the segments. Veins transversely elongated, and 
distantly anastomosing. Fronds flaccid, of t^vo kinds: sterile — pinnatifid or bipinnatifid, sinuate and 
viviparous; fertile — contracted, decompound, membranous, multifid, ■with linear forked and viviparous 
segments having their margins reflexed 
and indusiform. — Named from keras, 
keratos, a horn, and ijteris, a fern ; 
alluding to the fertile fronds. 
The peculiar habit and structure of 
this genus render it difficult to deter- 
mine its real affinity. The spore-cases 
are sessile, large and globose, furnished 
either with a broad nearly complete, or 
very short nearly obsolete ring. It was 
originally associated with Gleichen- 
iacece. Fig. 21 represents portions of 
the sterile and fertile fronds (nat. size), 
with a portion of the fertile frond 
magnified, showing the position of the 
sori. 
1. C. THALicTROiDES, Brongniart (Ello- 
EOCARPUs OLERACEus, Kaulfuss). — A Very 
singular annual aquatic stove Fern, native 
of the tropics of both hemispheres. Fronds 
glabrous, of two kinds : sterile — bipinnati- 
fid, one to one and a half foot long, reclin- 
ing, ■nuth oblong obtuse segments ; fertile 
— contracted, erect, three or four times pinnate, one and a half to two and a half feet high, with linear rovolute 
segments. Both forms are viviparous, of a light green, with the stipes nearly quadrangular. 
C. Parkbri, J. Smith (Parkeria pteroides. Hooker and Bauer), was raised by Mr. H. Shepherd, of Liverpool, 
and so closely resembles the Ceratopteris thalictroides, in all respects except the elastic ring of the spore-case, that 
it is only to be discriminated by the aid of a very powerful microscope. Mr. I. Smith informs us that he has 
raised C. thalictroides from the spores of this supposed species. 
Trihe AcROSTicHEiE, J. Smith.— '&>oxi amorplioitP, witliont r.n indusium. 
The species forming this extensive natural group are probably the easiest of all Ferns to recognize, 
from the sori being spread generally throughout the under surface of the frond. The species were 
originally comprehended under two or three genera; but they have been subdivided into nearly twenty. 
They have distinct sterile and fertile fronds, in which respect they are similar to Lomaria, in the tribe 
Fteridece, but they are at once distinguished from that group by the absence of an indusium, with 
which the Lomarias are furnished. Their most obvious point of distinction from Folypodaecn is in the 
sori being amorphous ; that is, not produced in round or linear masses, but closely occupying an 
irregular portion or the whole of the fertile disk, w'hich in one or two genera is not confined to the 
inferior surface alone, the contracted rachiform segments being sporangiferous on both sides. 
G 
