268 



SYSTEMATIC BOTANY 



acorus), Foetid Iris or Gladdon (Iris foetidissima) , Crocus 

 vernus and C. nudiflorus. 



Order Orchidaceae, Orchids. Perennial herbs. 

 Flowers hermaphrodite and irregular. Perianth 

 usually petaloid, of six lobes, the inner median one 

 generally forming a lip or labellum. Stamens reduced 

 to one, rarely two. Carpels three, syncarpous ; ovary 

 inferior, one-celled ; placentation parietal and bearing 



Fig. 179. Floral Diagram of Orchis. br, bract. 



numerous minute ovules. Axis of flower prolonged as 

 a column above the ovary, bearing the stamens and 

 stigmas. Fruit a capsule and contains very many 

 minute seeds. Floral formula P3 + 3, ai + o or 



+ 2, G ( 3) (Fig. 179). 



This order is a very large one, with 400 genera and 6,000 

 species ; eighteen genera and fifty species occur in Britain, 

 many of which are rare. They are most abundant in the 

 tropics, and differ widely in structure according to their 

 mode of life and habitat ; many occur as epiphytes on the 



