COMPOSITE. 207 



SONCHUS Sow Thistle). There are five stamens with 

 separate filaments attached to the corolla tube, and 

 rather long narrow anthers connected to each other by 

 the edges and forming a brown cylindrical box round 

 the style. In all cases, except ADENOSTEMMA, each 

 anther has at the top a small triangular flap, and these 

 together close the top of the box and so protect the 

 pollen which is shed inside out of the anthers ; but in 

 some genera the bases of the anther lobes are rounded, 

 in others produced downwards in slender tails. This 

 last distinction is of considerable importance : it is used 

 for instance to distinguish the VERNONIA tribe from the 

 EUPATORIUM tribe. The ovary has a single chamber 

 with one ovule and a single style divided at the top into 

 two stigmatic branches. These branches open out only 

 after the style has pushed its way upwards between 

 the anthers (pushing up pollen as it does so) : and since 

 all the florets do not come to maturity together, but 

 the outermost first and the most central last, one can 

 usually find styles in all stages in one head. The stig- 

 matic branches vary considerably in shape, being long 

 and pointed (subulate) or flattened on one side or thick 

 and cut off square (truncate) or they end in a conical 

 thickening. The fruit is dry and indehiscent, and termed 

 an achene. In some cases it has a tuft or circle of hairs 

 (pappus) or scales at the top, but in others it is quite with- 

 out them (Chrysanthemum, Sunflower). It contains one 

 seed with oily endosperm. 



The family is a very large one of about 10,000 species or 

 one-tenth of the whole phanerogamic Flora of the world and 

 found in all regions and especially on mountains. The method 

 of cross-pollination is very good (see below) ; and where-there 

 is a pappus to the fruit which allows it to be carried great 

 distances by wind, a species is able to spread rapidly on new 

 ground Curiously enough, however, we find as a matter of 

 fact that most of the species are very local. 



