MONOCOTYLEDONES 327 



f erior ; six stamens attached to the receptacle or to the perianth 

 tube; ovary free, sviperior, 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 fajnily 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 speciesi 

 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 ntimerous 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 ISTorth 

 America and in northern Europe . 



History. — The common onion is p^robably 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. saiivurn) is a 

 European perennial herb; Leek (.4. porrum) is a biennial .vhich 

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

 schosnoprasum) 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. 



