ROSALS. 467 
and airy foliage with the venerable walls and tracery of the 
windows. ; 
The Ash, however, is an enemy to all interloping vegetation ; 
its rapid growth exhausts the soil of all organisable substances, 
and the extension of its roots may be traced in the languid growth 
of its vegetable neighbours. : 
The Weeping Ash (F. pendula) has all the characters of the 
Common Ash, while the tendency of its branches is to bend down- 
wards, so that the arching boughs, when grafted on a stem of 
suitable height, will soon reach the ground, and form a natural 
arbour. Probably F. excelsior, if weighted at the extremity of the 
branches, would have the same tendency. 
The Soranaces, or Nightshades, are natives of all parts of the 
world without the polar circle, but they culminate in number 
and energy in the tropics. At first sight it would seem an 
anomalous system which places the Potato and the Love Apple 
in the same order with the Deadly Nightshade and Henbane; but, 
as De Candolle remarks, “it is not to be lost sight of that all 
our food should include a modicum of an exciting principle, 
which if it existed in greater quantity would be injurious, but 
which in moderate proportions is only a natural and necessary 
condiment.” Besides, as Dr. Lindley says, the apples, or fruit, of 
the potato are narcotic, although the tubers are wholesome and 
nutritious when cooked. Many plants of this order are used in 
medicine, Henbane (Hyoscyamus), Deadly Nightshade (Aéropa), 
Bitter-sweet (Solanum), Stramonium 
(Datura), and Tobacco (Nicotiana) 
being the chief and most valuable. 
If we examine the Potato (S. s 
tuberosum) as a type of the family, ‘&, 
_ We find the calyx (Fig. 426) is mono- 
Sepalous, with five divisions; the 
corolla monopetalous, and shaped like 
a wheel or cup, having lobes alter- * ae peomre 
nating with the division of the calyx, woe 
five stamens with short filaments, and bilocular anthers, opening 
at the summit by two spores. The pistil consists of a superior 
_ Ovary, surmounted by an — style, which terminates in an 
Seen : i 3 ! : 
