4 



THE YOUNG 



NATURALIST. 



seed like the car of a balloon, sails 

 away on its aeronautical voyage, the 

 gentle zephyr, or blustering boreas 

 alike helping it to its destined haven. 

 The extensive Natural Order Compos- 

 itse, comprising over 10,000 species, 

 doubtless owes its universal distribu- 

 tion, and immense assemblage of 

 individuals to this power of aerial 

 perambulation. It furnishes the best 

 and most varied illustrations of this 

 type, which is present in all its 

 members, although sometimes reduced 

 to a mere rim on the top of the fruit, 

 as in the daisy. In some others it is 

 so conspicuous as to give the name to 

 the genus, as in the groundsels 

 {Senecio — Senex, an old man) from 

 the white pappus, resembling the 

 snowy hairs of patriarchal age. And 

 the popular names of hawksbeard 

 [Crepis] and goatsbeard {Tragopogon) 

 refers to the same feature. The pappus 

 is well shown in the fruit of valerian, 

 and in a modified form in the hairs of 

 the cotton sedge [Eriophorum) , whose 

 nodding plumes of snowy whiteness are 

 so conspicuous all through summer 

 and autumn in wet uplands, moors, 

 and mosses. Similar to these are the 

 hairs which invest the ovaries of certain 

 grasses, as in the wild oats {Avena), 

 and the reed grass [Phragmites). A 

 like function is performed by the hairs 

 attached to the seeds of willows [Salix) 

 and the willow-herbs {Epilohium) which 

 is the only thing in common, except 



the popular name betwixt these two 

 widely separated genera. It may be 

 mentioned here that the cotton of 

 commerce is the exactly analagous 

 hairs found in the ovary of the cotton 

 plant. In the other type of this 

 division, the appendage is widened out 

 into a membraneous wing (a samara) 

 which acts like a sail or vane, as in the 

 " keys" of the ash and sycamore, this 

 is a favorite form of fruit in forest trees, 

 as in the elm, birch, hornbeam, and in 

 slightly altered form in the limetree 

 and hop. It is visible in the winged 

 fruits of umbelliferae, as the cow- 

 parsnips {Heracleum), and angelica. 

 Exactly the same device is seen, and 

 similar work is enacted by the winged 

 seeds of pines and firs. When the 

 woody scales of the cones open, the 

 samara-like seeds fall out, and getting 

 a good start from their elevated po- 

 sition are readily wafted to a distance 

 by the breeze. Of the third class we 

 have comparatively few illustrations 

 in Britain, one of the commonest and 

 most effective, the wood sorrel we have 

 already described in detail (see Y.N., 

 vol. i., p. 366. An allied plant, the 

 " touch-me-not " balsam (Impatiens 

 Noli-me4angereJ is often cultivated, 

 and may occasionally be met with 

 semi- wild in shrubberies. As its name 

 implies, it is very impatient of contact : 

 as the pods approach maturity they 

 become ruptured by the slightest touch 

 and scatter the seeds to some distance. 



