604 DIOSCOREACE.E. 



introduced from the Crimea, differs mainly from the 

 common species in having broader, plaited leaves, and 

 somewhat larger flowers. Fl. January March. Per- 

 ennial. 



3. LEUCOJUM (Snowflake). 



1. L. cestivum (Summer Snowflake). A doubtful 

 native, found occasionally in moist meadows in many 

 parts of England. A bulbous plant about 2 feet high, 

 with narrow, keeled leaves, and 2-edged flower-stalks 

 bearing each an umbel of rather large white flowers, 

 the sepals and petals of which are tipped with green. 

 It is a common garden plant. Fl. May. Perennial. 



ORD. LXXXVL DIOSCOKEACE^E. YAM TRIBE. 



Stamens and pistils on different plants (dioecious) ; 

 perianth 6-cleft ; stamens 6, arising from the base of the 

 perianth ; ovary inferior, 3-celled ; style deeply 3-cleft ; 

 fruit a dry, flat capsule, or (in Tamus, the only British 

 species) a berry. Twining shrubs or herbs, approaching 

 in habit some of the Dicotyledonous Orders, the leaves 

 being decidedly stalked, and having netted veins ; the 

 flowers are small, with 1 3 bracts each, and grow in 

 spikes. The Order is a small one, and is, with the ex- 

 ception of Tamus (Black Bryony), confined to tropical 

 regions. Dioscorea, the plant from which the Order takes 

 its name, has large tuberous roots, which, under the name 

 of " Yams/' form as important an article of food in 

 tropical countries, as the Potato in temperate climates. 

 When growing it requires a support, like the Hop. 

 There are several varieties ; the best are white and 

 mealy, but some are yellow and watery, with a slightly 

 bitter taste. 



1. TAMUS (Black Bryony). Characters- described 

 above. (Name, the Latin name of the plant.) 



