186 The Romance of Wild Flowers 
number of rays, which vary from eight to twelve. 
The disk-florets are greenish, and the strap-shaped 
leaves are simply toothed, instead of being deeply 
divided. 
It is worthy of notice that many of the plants we 
have just been describing have developed strong 
bitter, tonic, and astringent properties, which cause 
them to be disliked by browsing animals; even the 
caterpillars that eat them are few in number. Tansy 
(Tanacetum vulgare) and the Wormwoods(Artemisia) 
share in these bitter properties, and have long been 
esteemed in medicine for their vermifugal qualities. 
Tansy 1s an example of a Composite that has not yet 
gone in for rays. All the florets are tubular and 
yellow, but the outer series is so far differentiated 
that the florets contain pistils only. In the Worm- 
woods the yellow or reddish heads are very small— 
about one-sixth of an inch in diameter—but crowded 
together in panicles or racemes. In spite of this 
massing, they are very inconspicuous, and do not 
attract insects; they are fertilised by the wind, and 
consequently their pollen is smooth—a condition 
quite exceptional in the pollen of this family. 
The closely allied though separated Coltsfoot and 
Butterbur are interesting as examples of plants that 
produce flowers long before a leaf appears above 
ground. Coltsfoot (Tussilago farfara) 1s a well- 
known weed of stiff soils, in which its rootstock 
burrows deeply, branching in all directions. About 
the end of February an unopened drooping flower- 
head pushes through the earth, supported on a cottony 
stalk partially covered with oblong scales. The 
flower-head opens and looks like a large Daisy with 
