CULTURE OF THE GENUS VIOLA. 1]5 
necessary for the fixture of them, to avoid being displaced in the watering, 
which should be liberally supplied while they are striking root. 
Many of the sorts will have formed good roots in the course of eight or ten weeks, 
whilst others will require as many months. In Autumn and Spring, the cuttings 
should be placed in a shaded part of the stove ; but, in the Summer season, they 
will succeed equally well in a cold frame, shaded from the mid-day sun. Mr. 
Muirhead, a very successful propagator of the Ericese, formerly plunged his pots 
in coal-ashes, behind a north-wall, in the Summer season, where they were covered 
with hand-glasses, and removed in Autumn to the Pine-stove. The cuttings will, 
in general, strike root more readily by being covered with bell-glasses, the size of 
which must be regulated by the pots, and be occasionally wiped, when there appears 
an accumulation of moisture on their inner surface ; but these glasses may consist 
of those with holes in their tops, which will permit the moisture to evaporate, and 
prevent it, in a great measure, from injuring the cuttings. Mr. M‘Nab, however, 
and the Messrs. Loddidges, both consider these glasses unnecessary, except for a few 
sorts. When the cuttings begin to grow freely, it is generally a sure sign of their 
having made roots ; they should then be taken carefully out, and put into the 
smallest sized pots that are made, placing four or five round the sides of each, and 
then placed under a hand-glass, and shaded, until they begin to make young roots 
in the fresh soil, when they may be gradually exposed to the sun and air ; and when 
they appear to be of sufficient strength, and their roots well established in the soil, 
they should be planted singly into small pots, and afterwards treated in every respect 
the same as was mentioned for the seedlings. The culture of the Ericea is rendered 
more easy by their being seldom attacked with insects ; the green fly will occasion- 
ally infest some of the plants, but it is easily eradicated by fumigation, or by dipping 
the infected shoots into a decoction of tobacco-water ; some of the species are, also, 
subject to mildew ; but this is likewise readily subdued, by dusting a little sulphur 
over the affected parts ; the most effectual preventive for the disease, however, is a 
free circulation of air amongst the plants. 
CULTURE OF THE GENUS VIOLA. 
This genus contains more than a hundred species and varieties, the greater 
part of which are ornamental and deserving of notice. They are chiefly hardy, 
and will thrive in a mixture of peat and loam; and, with a few exceptions they are 
very low-growing plants. The tender species are, V. arborescens , decumbens , 
humilis , ccespitosa, pygmcea , betoniccefolia , and Broussonetiana. These may all be 
treated as half-hardy plants ; and all, with the exception of arborescens , may be 
propagated by division of the roots. The V. arborescens may be either increased 
by cuttings or layers. The best time to put in the cuttings is as early in the 
spring as they can be obtained, generally in March. They are easily struck if 
