MONOCOTYLEDONES 327 



ferior ; six stamens attached to the receptacle or to the perianth 

 tube; ovary free, superior, and three-chambered; few to many 

 seeds in each chamber ; style simple or three-cleft ; fruit a capsule 

 or berry; leaves simple, entire and sessile (Figs. 165 and 166). 



The members of this family are widely distributed 

 throughout the world, especially in the temperate zones. The 

 family contains a number of ornamental plants and a few culti- 

 vated vegetables. 



The onion (the genus Allium] includes a number of species 

 and varieties which are of commercial importance. The common 

 onion is A. cepa. The valuable part of this plant is the well- 

 developed bulb made up of a short conical stem to which are 

 attached numerous sheathing leaves with thickened bases. The 

 terminal bud sends up a long hollow or sometimes solid, leafless 

 stem which bears an umbel inflorescence. Some species produce 

 numerous bulbs at the apex of this stem. A mass of fibrous 

 roots is developed from the lower end of the stem. The flower 

 is regular, perfect and consists of a six-parted perianth, six 

 stamens and a. single superior ovary. The pollination is by 

 means of insects. The fruit is a three-chambered membra- 

 nous pod or capsule. Two black seeds are borne in each capsule. 



This genus includes about 250 species, mostly in North 

 America and in northern Europe . 



History. The common onion is probably a native of south- 

 western Asia and has been cultivated for so long that its early 

 history is lost. During this long period of development many 

 commercial varieties have appeared. 



Other Important Species. Garlic (A. sativ^m} is a 

 European perennial herb; Leek (^4. porru-m,} is a biennial .vhich 

 is a native of the Mediterranean districts of Europe; Chives (A. 

 schcenoprasum] is a perennial which is grown extensively in both 

 the old and the new world; the field garlic or wild onion (A. 

 vineale) is a European plant which has been introduced into 

 the United States and has become a very troublesome weed. 



