PHYSIOLOGY. 263 
Q 257. 
Not all plants do grow in earth, and therefore the 
root does not enter the ground. ‘The parasitic plants 
are an exception of this kind. The Cuscuta ewre- 
pea, dodder of thyme, when it germinates, lengthens 
its filiform plumule, winds round neighbouring 
plants, as flax, nettles, &c. and runs along them. 
[ts rostel decays, and along the whole surface of 
the filiform branchy stalk a kind of warts shoot out, 
where it rests upon the other plants, serving as roots. 
Algae, but especially Lichens, are, by similar warts, 
attached to the trunk of trees, and few pierce their 
external membrane. ‘The Sphaeriae grow mostly on 
the inner bark of old decayed trees; they pierce or 
elevate the external membrane, and are firmly at- 
tached by wart-like roots. ‘The mistletoe, (Viscum 
album), pervades with its roots the woody part of 
branches, and becomes intimately blended with 1. 
Amongst the numerous species of parasitic plants 
which the torrid zone produces, one species de- 
serves notice, which grows abundantly in the Indies 
beyond the Ganges, the Epidendrum los aéris, for 
it grows and blossoms in the air, when hung up. 
Mr Loureiro, who saw this himself, assures us, that 
it vegetates hung from the ceilings of rooms for 
years, and is uncommonly grateful to the inhabi. 
‘tants by the fine odour of its blossoms. 
jj § 258. 
The root is indeed, in the strictest signification, 
the very plant itself, ‘Che stalks, leaves, and flowers 
R. 4 iSSUIng 
