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II. The Pappus , or Down, attached to some kind of seeds, gives them 
the exact appearance of shuttle-cocks, and forms them for an aerial flight, 
being an admirable contrivance of Nature to disseminate her productions, and 
thus render common to different territories, individuals of the same species, 
which, without such precaution, might have been confined to one. The 
pappus is, indeed, one of the most wonderful contrivances employed by the 
liberal hand of Nature for distributing her vegetable productions over the 
surface of the globe. There can be little doubt but that many species of 
plants, particularly among the compound flowers, owing to their being sup¬ 
plied with the pappus , have extended themselves over countries where they 
were not the original natives. Thus about an hundred years ago the Cana¬ 
dian Fleabane (Erigeron Canadense) was introduced from Canada into 
the botanic garden at Paris, and it is now found spread over France, Hol¬ 
land, Germany, and Italy. 
Thus the seeds of the Thistle (Carduxjs), Blue-bottle (Centaurea), 
Dandelion (Leontodon), Succory (Cichorium), and Groundsel (Senecio), 
being furnished with pinions, plumes, or tufts, are conveyed to a prodigious 
distance, and hence appear to have a true locomotive power. 
Some of these pinions are actually barbed , as in the Feather-grass 
(Stxpa), where the awn (arista) is from six to twelve inches in length, or 
even more, nodding, angular, twisted at the base, and clothed almost the 
whole length with very fine white pellucid divergent hairs 7 which at first 
occasion the seeds of this grass to be carried to a distance by the wind; and 
when these have acquired their hold in any place, being actually screwed 
into the earth by the twirling of the arista , the pennre , or wings , break off*, 
and leave behind the imbedded seed. 
There is not a single vegetable, remarks the benevolent James Henry 
Bernardin de Saint Pierre, in his Studies of Nature, the leaf of which 
is disposed to receive the rain-water on the mountains, whose seed is not 
formed in a manner the best adapted to raise itself thither. The seeds of 
barley is furnished with stiff points, which, like the teeth of a saw, are all turned towards one end 
of it; as this long awn lies upon the ground, it extends itself in the moist air of night, and pushes 
forwards the barley-corn , which it adheres to; in the day it shortens as it dries; and as these points 
prevent it from receding, it draws up its pointed end, and thus, creeping like a worm, will travel 
many feet from the parent stem; and may thus be used as a travelling hygrometer , when laid on a 
cloth on the door, like the automaton of Mr. Edgeworth, described in the Botanic Garden by Dr. 
Darwin. 
