212 SOUTH AFRICAN FLOWERING PLANTS. 



in the colour of several plants of this order, in that they 

 are red when first opening ; but the colour changes to 

 blue or purple afterwards. 



This individual alteration is supposed to correspond 

 with the development of colours in the floral world. 

 The primeval colour was probably yellow ; next 

 followed reds, then purples, and finally blue. When a 

 red chrysanthemum or other plant throws out a yellow 

 blossom, called a " sport," it is said to revert to the 

 ancestral, or original, colour. 



Lithosper'mum. — This genus is so called from the 

 polished, stone-like fruits. This is due to the secretion 

 of lime in the ovary- walls which tightly invest the seeds. 

 There are seven or eight South African species consist- 

 ing of herbs or under-shrubs. 'The flowers are mostly 

 small, of various colours. 



General Description of the HeliotroiJC Family. 



JTerhs, shruhs, or trees. 



Leaves — Alternate, with rough or bristly hairs. 



Flowers — On scorpioid racemes ; calyx, 4- to 5-parted, 

 persistent ; corolla regular, often rotate, or irregular 

 {E'chium) ; stamens, as many as petals and adherent 

 to corolla; ovary, of 2 carpels, but 4-lobed. 



Fruit — Separating into 4 nutlets or drupe-like. 



