345 



The Thistle Family. 



(Composite.) 



Herbs, frutlets, or shrubs, rarely trees, with alternate, 

 simple, entire, or variously divided leaves ; often heath-like, 

 or large and of rounded form 1 foot or more in diameter. 

 Flowers in heads consisting of numerous florets seated on a 

 common receptacle, surrounded by an entire or many-scaled 

 involucre, corolla tubular, equal, or the exterior side of 

 the limb of the tube extended in the form of a petal-like 

 lobe or strap, termed ligulate or bilabiate ; florets uni- 

 sexual, bisexual, or neuter. Stamens 5, the anthers united, 

 forming a cylinder round the pistil which is simple, with a 

 bifid apex. Fruit a dry 1-seeded achenia, crowned with 

 the permanent scariose or plumose feathery calyx. 



The whole of the plants of this family are included in the 

 19th Class, Syngenesia of Linngeus (see page 81). 



In natural arrangement this extensive family is divided 

 into 3 sub -families. 



1st. Ligulijlorce, in which the florets are all ligulate, and 

 correspond with part of the first order, jEqualis, of Lin- 

 naeus, and are characterized by being furnished with a milky 

 juice. 



2nd. Tuhuliflorce. In this the florets are in the form of a 

 tube, straight or curved, 4 or 5 dented, or more deeply cleft 

 and bisexual, often with pistil bearing or barren ligulate 

 rays. 



3rd. Labiatifiorce. In this the florets are bilabiate ; that 

 is, 2 -lipped. 



This, the largest family of plants, consists of between 

 9000 and 10,000 species, and may, therefore, be considered 

 as forming about one-tenth part of the whole vegetable king- 

 dom. They are found in all parts of the world where plants 

 ' can grow, but it is remarkable that but few of them assume 

 the character of trees. A considerable number are small 

 shrubs, but the greater mass are herbaceous perennials and 



