588 BOTANY OF CROP PLANTS 



pears that their recovery prevents the prompt development 

 of new ones. 



Leaves. — The leaves are usually alternate, always com- 

 pound, odd-pinnate, and petioled. In all tomatoes except 

 L. esculentum var. grandifolium and possibly L. pimpinelli- 

 folium, the leaflet margin is toothed or lobed. 



Inflorescence and Flowers. — The flowers are commonly 

 in raceme-hke cymes, or in racemes (as in currant tomato). 

 However, even in the currant tomato the racemes are often 

 branched at the tip. The flowers are perfect, regular, and 

 pendant. The calyx is five- to six-parted; the segments are 

 linear or lanceolate, .persistent, and increase in size with the 

 development of the fruit. The corolla is rotate or wheel- 

 shaped, cleft into usually five, sometimes more, lobes; the 

 tube of the corolla is short. There are five stamens (some- 

 times more) attached to the corolla tube; the filaments are 

 very short, and the anthers open by a longitudinal sht on 

 the inner side; they are elongated, connate or connivent. 

 There is one pistil bearing a single style and an ovary, which 

 is usually two-celled (more than two-celled in cultivated 

 tomatoes) and has a central, fleshy placenta. 



Pollination, Fertilization, and Development of the Fruit. — 

 In the maturing of the flower, the style elongates and pushes 

 the receptive stigma through the tube formed by the anthers. 

 In some instances, this elongation occurs prior to the dehisc- 

 ing of the anthers, hence eliminating the possibility of self- 

 pollination. Sometimes the anthers shed pollen at the time 

 the stigma is pushed upward; and in the growth of the stigma 

 it rubs against the dehiscing surface of the anthers. Stigmas 

 remain receptive for several days. However, it is known 

 that greenhouse tomatoes do not set fruit well unless arti- 

 ficially pollinated, as is commonly done by jarring the plants 

 at the time of anther dehiscence. Natural cross-polUnation 

 seldom occurs. 



