THE SPIDER-WORT AND ASTER FAMILIES. 245 



seeds or by cuttings of the young growth in heat. R. 

 hybrids is a garden hybrid obtained in Belgian gardens, 

 sent out by Mr W. Bull, and useful for the sake of its pink 

 fragrant flowers. Parents not precisely known. 



THE SPIDER- WORT FAMILY (Commelynacece). 



A small family of erect or scandent and mostly evergreen 

 tropical herbs, represented in our gardens by various species 

 of Tradescantia, Commelyna, Cyanotis and Dichorisandra. 

 The hermaphrodite, triquetrous flowers are commonly white, 

 blue, or purple in colour, and are generally distinguishable 

 by the beautiful silky hairs which clothe the filaments. 

 They are chiefly natives of the East and West Indies, 

 New Holland, and Africa, a few occurring in North America, 

 but none in Europe or North Asia. They are readily 

 multiplied by seeds whenever obtainable, and these should 

 be sown as soon as ripe on pans of well-pressed light sandy 

 compost, after which cover with a green pane of glass or 

 a sheet of brown paper, and place on a gentle bottom- 

 heat to germinate. Division is practicable in the case of 

 Tradescantias and Dichorisandras, while cuttings of the young 

 and partially - hardened growth root freely in a close case. 

 The hardy Spider -worts are readily multiplied by careful 

 division. 



THE ASTER FAMILY (Composite). 



The largest of all the great orders into which botanists 

 divide plants, nearly 9000 species being known, and these 

 are distributed over nearly the whole surface of the earth. 

 It is interesting to observe the curious structure and growth 

 of the bilobed style in nearly all Composites. If the disc- 

 florets of a single Dahlia (see fig. p. 254) or a Daisy be examined, 

 it will be seen that the five anthers are syngenesious that is, 

 joined together at their margins in such a manner as to form 

 a short tube ; and owing to the slower or later development of 

 the style, it is concealed below these anthers until they are 

 ready to discharge their pollen, and just at this time it com- 

 mences its upward growth through the tubes formed by the 

 anthers, its two lobes being firmly adpressed so as to prevent 

 any pollen lodging on their inner faces (stigmatic surface). The 

 top of the style thus presents a knobbed or club-shaped appear- 

 ance, and is set with stiff, sub-erect, short hairs or bristles, the 



