IS2 



DICOTYLEDONS 



Type : NIGHTSHADE {Solanum nigrum). 



A 



— Floral diagram of 

 Solanum. 



Vegetative characters. — Annual herb. Leaves exstipulate, 

 alternate, but near the flowering portion of the stem the 

 leaves are seemingly arranged in 

 pairs of one large leaf and one 

 smaller one at a node. The branch- 

 ing is really cymose, and each in- 

 florescence appears to spring from 

 the side of the stem, yet not to arise 

 in the axil of a leaf.* Inflorescence 

 cymose ; note that no prophylls are 

 visible on the flower-stalks. Flower 

 (fig. 84) actinomorphic, $ , cyclic, 

 hypogynous. Sepals (ex) five com- 

 bined. Petals {co) five, combined. 

 Stamens (a) five, alternating with 

 the five petals and inserted on the 

 corolla-tube ; the anthers are close together in the centre 

 of the flower, each opening by two pores at its summit. 

 Carpels two, syncarpous, superior. Ovary (pv) two-chambered, 

 with many ovules on a thick axile placenta. Style one. Stigma 

 {sg) one. [Try and see that the two carpels are not median 

 or transverse in position, but are oblique.] Pollination. — The 

 flower has no nectary, but is visited for the sake of its pollen. 

 Fruit a berry. Seeds kidney - shaped. Dissemination. — 

 In spite of their being poisonous, the berries are eaten by 

 birds, which consequently are responsible for the dispersal of 

 the seeds. 



The Potato-plant {Solanum tuberosum) has flowers so similar 

 to those of the Nightshade that they may be selected for examin- 

 ation in place of the latter. The plant is a perennial with 

 subterranean tuberous shoots. The unequal size of the leaflets 

 composing a leaf is specially worthy of note (fig. 48). 



USES, PECULIARITIES, etc. of Solanace^e. 



Many Solanaceae contain powerful poisons, some of which 

 are used as medicines. Belladonna is obtained from Atropa 



* This characteristic method of branching, and the peculiar paired 

 arrangement of the leaves, cannot be explained in this book. 



