ALLIUM CEPA i8i 



mation of the bulb of commerce. (Fig. 8i.) The inner leaves 

 emerge through the outer ones by way of a lateral slit at the apex of 

 each leaf base. The linear blade is parallel-veined and cylindrical, 

 with a hollow center at maturity. This is not continuous with the 

 hollow formed by the circular leaf base, but is the result of a 

 splitting away and disintegration of the centrally located paren- 

 chymatous tissue. 



The Inflorescence and Flower. — The inflorescence is a 

 terminal umbel that is borne on an elongated flower stalk which 

 reaches an average height of 3 or 4 feet, but may occasionally 

 approach 6 feet. It is subtended by a papery spathe consisting of 

 two or sometimes three bracts which enclose the umbel until it is 

 split by the development of the first flowers. (Fig. 82., A.") The 

 number of flowers in an umbel ranges from as few as 50 to over 

 1000. The pedicels which bear the individual flowers are usually 

 long and slender, but may be short and rigid. The flower buds do 

 not develop in regular centripetal or centrifugal order; and, con- 

 sequently, flowers in various stages of development occur through- 

 out the umbel. 



The white or bluish flowers are regular and pentacyclic, consist- 

 ing of a perianth of six similar parts arranged in two whorls, six 

 stamens inserted at the base of the perianth segments in two cycles, 

 and a pistil of three undiverged carpels. (Fig. Sx, E, G.) The 

 nectaries occur in the axils of the three inner stamens. The ovary 

 is superior and there is a single, thin persistent style with a slightly 

 three-lobed stigma. The anthers of the inner whorl of stamens 

 dehisce before those of the outer, and both sets do so before the 

 stigma is receptive. For this reason, cross-pollination is the rule 

 and is effected through the agency of insects, although inter- 

 pollination between flowers of the same umbel is undoubtedly a 

 frequent occurrence. 



ANATOMY 



The Fruit and Seed. — The fruit is a three-lobed, three-celled 

 capsule, each valve or locule containing one or two black seeds at 

 maturity, and the dehiscence of the fruit is loculicidal. Sachs (15) 

 has described the seed, and the development of the seedling has 

 been outlined by Anderson (i) and Hoffman (7). Kondo (11) in- 

 vestigated the structure of the seed coats of several species of Allium 

 and found them to be similar in all major details. 



