206 LETTER XVII. 



when the florets expand, of closing when the corollas 

 fall ofi^, in order to confine the young fruit ; and 

 lastly, of opening again and turning quite back to 

 give more room to the fruit, which increases in size 

 as it grows ripe. This is particularly remarkable in 

 the Dandelion. 



Let us now pass from these considerations to a 

 view of the sections into which Composite Flowers 

 are naturally divided. 



If you gather a head of Dandelion (Leontodon 

 Taraxacum), you will find that both the ray and the 

 disk are composed of ligulate florets, to the total ex- 

 clusion of tubular ones. Such plants are called Suc- 

 cory-headed (Cichoracese), and are remarkable for 

 their stems yielding a white milk, which, when con- 

 centrated, has a soporific quality. The other sections 

 are destitute of this property. Here are arranged num- 

 bers of our wild flow ers, such as Goat's beard (Trago- 

 pogon), Sow Thistle (Sonchus oleraceus), Wall Lettuce 

 (Prenanthes), Hawkweed (Hieracium), and the shabby 

 Succory (Cichorium Intybus), with its ragged leaves, 

 and pale blue florets. It is also to this section that the 

 Lettuce and Endive of the garden belong. 



From the last you will easily distinguish what 

 is called the Thistle-headed section (Cinaraceae). 

 These plants have no ligulate florets ; all the florets 

 are tubular, generally very wide at the mouth, and 

 so much spreading beyond the involucre as to give 

 the flower-head almost an hemispherical form. The 

 leaves of the involucre are also, in most of the species, 

 hard and spiny. It is in this section that you will 



