A Dictionary of Choice Ferns. 
317 
With the exception of the varieties of S. vulgare, 
which are usually and with greater certainty in- 
creased by the division of their crowns (and a few 
by means of the bulbils produced on their fronds), 
the propagation of Scolopendriums is effected by 
spores, which are abundantly produced and germi- 
nate freely. 
5. vulgfare. 
This ornamental hardy species is a native of various parts 
of Europe, Madeira, the Azor-eis, and the Caucasus, as well as 
Japan, and North and South America; but there are no 
records of its having been found in any part of India. It is 
among the rarest of American Ferns. The fronds of 
this species are Gin. to 18in. long and l^in. to Sin. broad; 
they are borne on stalks 4in. to 8in. long land hairy at the 
base, are strap-shaped, entire, usually bluntish at their 
summit, and heart-shaped at the base. Their texture is 
somewhat leathery and their colour usually bright green ; 
their fructification is abundant, generally more so towards 
the extremity. The narrow spore masses are mostly dis- 
posed in parallel pairs, oblique with regard to the midrib, 
and of a brownish-black colour, which has a most pleasing 
effect, the contrast with the bright g:reen tint of the 
frond being very strikina:. The really distinct varieties of 
S. vulgar e, either naturally produced or resulting from culti- 
vation, are extremely numerous, and differ so markedly from 
the type, that a description of the usual fronds gives but a 
very inadequate idea of the extensive variations found. 
Still, interesting as they undoubtedly are, it would be im- 
possible to describe even a tithe of the more noteworthy of 
such variations. Elsewhere is illustrated one of the most 
remarkable in >Sf. v. Kelwayii (Fig. 27) ; and for the rest 
we must refer readers to a work dealing especially with 
British Ferns or to the lists of nurserymen making them a 
speciality. 
SELLIGUEA. See Gymnogramme. 
STENOCHL^ENA. See Acrostichum. 
STRUTHIOPTERIS. See Onoclea. 
THYRSOPTERIS. 
This genus is coniT)Osed of a solitary and most 
interesting" species. It is a thoroug'lily distinct 
plant, requiring only greenhouse temperature, shade, 
and an abundance of water at the roots. The fructi- 
fication is totally different from that of any other 
