646 FLOWERS OF GARDEN AND GREENHOUSE 
are attached to the rootstock either in tufts or alternately, and are at 
first rolled up tightly with the tip of the frond in the centre of the coil, 
and the divisions of the frond rolled up in like manner. The frond-stalk 
is termed a stipes, and its continuation through the leafy portion of the 
frond is the rachis. The primary divisions of a frond are pinnw; the 
divisions of a pinna are pinnules. They are propagated by means of 
spores, similar in nature to those of Selaginella. In all the Ferns these 
are microscopic, and contained in very minute capsules (sporanges), 
which are in turn massed in heaps or ridges, known as sori, on the back 
of the frond, and frequently covered with an involucre or indusium. 
The species are widely distributed over all except the very cold and arid 
regions, chiefly abounding in the Temperate and Tropical, especially 
where there is humidity. The British species number thirty-eight, but 
of this small number about six hundred varieties are in cultivation at 
Kew. In the following descriptions the foot-stalk (stipes) and the leafy 
portion (frond) are measured separately. 
SHIELD FERNS 
Natural Order Finices. Genus Aspidium 
AspIDIUM (Greek, aspis,a shield: the form of involucre). A genus of 
about fifty-five species, with the sori globose, on the veins of the pinnules, 
covered by a roundish involucre attached by its middle. They are 
natives of all regions, and two species are found wild in Britain. 
We have as representatives of this genus in our native 
flora, Aspidium Lonchitis, the Holly Fern, which grows on 
northern alpine rocks, and A. aculeatum, the Prickly Shield Fern, 
which is widely distributed, not only in our own country, but throughout 
the world. Several species have been manufactured out of the varieties 
of A. aculeatum by “ splitting” botanists, and the garden varieties can 
only be represented by three figures. Several of the exotic forms have 
been in cultivation here for many years, though of most the date of 
introduction has not been recorded. A. trifoliatum,a Tropical American 
plant, was introduced from the West Indies in 1769 ; and A. auriculatum, 
from the East Indies, in 1793. 
ASPIDIUM ACROSTICHOIDES (Acrostichum-like). Stipes 
densely scaly below, 6 to 8 inches. Frond 1 to 2 feet long, 
2 to 6 inches across. Pinne 2 to 3 inches long, spiny-toothed, the lobes 
nearest the rachis enlarged, and looking like ears (auricled). The 
History. 
Principal Species. 
