2 THE DARWINIAN THEORY [ch. i 



The likenesses between plants are often less immediately 

 obvious, and as compared with animals they seem to have been 

 less remarked mitil a few centuries ago. One may see this lack of 

 observation upon the part of mankind in the common names 

 of plants, which are often old. Thus one often finds such names 

 as meadow-rue, marsh-marigold, rock-rose, sea-heath, wood- 

 sorrel, and the like, applied to plants that are in no way closely 

 related to the rue, the marigold, the rose, the heath, or the sorrel, 

 though they may have a superficial likeness in the leaves, in the 

 look of the flowers, in their colour, or in the taste. But at the 

 same time, one must also notice that many plants belonging to 

 the same families (as now recognised) have similar names. Thus 

 many Cruciferae, with their cress-like taste (cress itself is a 

 member of the family), have names like bitter-, penny-, rock-, 

 thale-, wart-, water-, winter-, and yellow-cress. The same taste, 

 however, occurring in the seeds of the garden Tropaeolum, that 

 plant used to be known as Indian cress, though it belonged to a 

 totally different family. This also illustrates the now familiar fact 

 that to place an organism in its proper relationships one must not 

 rely upon a single character only. The name vetch is common 

 among the British Leguminosae, and grass among the Gramineae, 

 though here again one finds members of other families, often 

 unrelated to the grasses, known as arrow-, cotton-, eel-, goose-, 

 knot-, scorpion-, scurvy-, and whitlow-grass, because of some 

 resemblance in habit, leaves, or other things. 



Gradually the true likenesses of plants began to be recognised 

 to such an extent that they were grouped into species and 

 genera within families, and these again within larger groups, 

 especially by the work of Tournefort, Linnaeus, Jussieu, Brown, 

 Endlicher, and many others of more recent date, so that now 

 we have what is probably a reasonably good classification of 

 them. 



Till about a century ago, the universally accepted view of the 

 origin of plants and animals was that they had been specially 

 created, each species in the form in which it now appears upon the 

 earth, whilst their varieties were formed later, as the areas 

 occupied by the species became larger or more varied. But it was 

 clear that though one might group together the buttercup family, 

 or the cat family, special creation would not explain, though it 

 made the need of explanation greater, why they should possess 

 such likenesses as caused them to be thus grouped together. 

 Since the time of Aristotle vague ideas had been floating about. 



