THE POTATO AND NIGHTSHADE FAMILY. 543 



one, but equally free and robust in growth, producing its large, 

 rich, dark, purplish-lilac, salver-shaped flowers in the early spring 

 and summer months. 



Nicotiana (Tobacco], The Tobacco of commerce is derived 

 from several species of sticky - leaved herbaceous plants or 

 annuals, mostly natives of tropical America and Eastern Asia, 

 Among those most generally cultivated, that which furnishes 

 the largest quantity of "weed" is N. tabacum, or JV. vir- 

 ginica as it is also called, this being largely cultivated in the 

 Southern American States, and also in China, Holland, Ger- 

 many, and S. France, Italy, and Spain. N. rustica, a dwarfer 

 and hardier species, is grown in the East Indian islands, and 

 furnishes the Latakia and Turkish Tobacco of commerce. It 

 is dwarfer, and grows and ripens more quickly, than the large- 

 leaved kind. There are many other species, and in this country 

 the large-leaved kinds have lately been much used in subtropical 

 gardening. All the species are cultivated as annuals, and are 

 most readily propagated by seeds sown in a gentle heat in the 

 spring. Many of the species may be hybridised with facility, 

 as demonstrated by Gaertner and others. N. rustica, fertilised 

 by pollen of N. paniculata, was made to produce two kinds of 

 seeds by " dusting half the stigma with the strange pollen 

 before the expansion of the flower, and the remainder after a 

 lapse of twenty-four hours ; and the conditions of the experi- 

 ment were varied until the pure type seeds of N* rustica 

 vanished entirely, and merely the hybrid or bastard type seeds 

 made their appearance." So susceptible, indeed, are the Tobac- 

 cos to hybridism, that even three kinds of seeds have been 

 produced by the same plant when fertilised by the pollen of two 

 other species. Here again Gaertner is the experimenter. N. 

 paniculata was successively fertilised with pollen of N. quadri- 

 valvis and N. Langsdorfii, and from the seeds produced by this 

 mixed union three proved to be the pure species (JV. pani- 

 culata), four the hybrid, N. paniculato-Langsdorjii, and a single 

 individual N. paniculato-quadrivalvis. Gaertner gives full de- 

 tails in his work, from which we learn that pollen of N. Langs- 

 dorfii will fertilise the following species, but the seeds are pro- 

 duced in a decreasing ratio in the order named : N. paniculata, 

 N. vincafoKa, N. suaveolens, N. glauca, and N. rustica^ though 

 not susceptible itself of being fecundated by these species, 

 neither by N. chinensis, N. macrophylla, W. quadrivalvis, and 

 N. glutinosa. Gaertner, who experimented largely with the 

 species of this genus, remarks that the want of perfect recipro- 

 city of sexual force, even in the most nearly allied species, 

 shows that the male and female procreative energy do not 



