CHAP, XII. POLYGALA‘CEX. © - -- 355 
that he found this species in dry sandy barrens in New Jersey, and - that 
he is much inclined to think it is only a variety of H. ericdides: they 
were both seen in abundance together; and many subvarieties were ob- 
served, which seemed to unite the two. This curious shrub covers large 
tracts of the dry white sandy plains of New Jersey, in large round tufts, 
where it resembles very much the common ling (Callina vulgaris) of Scot- 
land.” Were all botanists, who, like Mr. M‘Nab, are at once scientific 
observers and practical cultivators, to exercise their common sense, as he 
has done in this instance, we are persuaded that the namber of alleged species, 
in every genus which now contains a great many, would soon be con- 
siderably reduced. The flowers of this kind of hudsonia are small and 
yellow, and appear from May to July. Like H. Nuttall’, this is somewhat 
difficult of culture, requiring a peat soil, a shady situation, and protection 
by glass or by snow during winter. All the species are readily increased 
by layers, or by cuttings of the ripened wood, planted in sand under a hand- 
glass. 
App. I. Other Species of Cistacee. 
Long as is the list of Cistacew, and especially of helianthemums, in this 
chapter, it might have been increased by the addition of various other species, 
or sorts, described by botanists. The utility, however, of such additions is 
very questionable. We have confined ourselves, as much as possible, to sorts 
that are, or were lately, in existence in the neighbourhood of London ; and 
for this information we have taken as our guide the Cistinee of Sweet, com- 
menced in 1825, and completed, in one volume, in January, 1830. We think 
we may safely assert that several of the sorts described in that work are now 
no longer in existence; because, in consequence of their tenderness, and 
liability to be neglected, they are continually dying off during winter, and 
as continually being replaced by others raised from seeds, either imported or 
saved in this country. The chief use which we propose to ourselves, in giving 
so long a descriptive list, is, to show the numerous and beautiful forms assumed 
' by this family of plants, in order to promote their more extensive cultivation. 
Supposing a cultivator about to form a collection of Cistacew, we should 
attach much less importance to his being able to procure all the sorts described 
by Mr. Sweet, than to his obtaining all the sorts easily procurable, whatever 
names they might pass under, and cross-fecundating them, so as to produce 
new forms. There can be no doubt whatever that the sorts of both the genera 
Cistus and Heli4nthemum might, by cross-fecundation, be increased ad in- 
jinitum ; and, considering their very great beauty as border and rockwork 
shrubs, we think they merit the attention of cultivators at least as much as 
many florist’s flowers. 
CHAP. XII. 
— 4a_ 
OF THE HARDY AND HALF-HARDY LIGNEOUS PLANTS OF THE ORDER 
POLYGALA‘CEX, 
-TuERre is only one perfectly hardy ligneous plant belonging to this order, and it is of such humble 
growth, that, for all practical purposes, it may be considered as a herbaceous plant, rather than as a 
shrub. ° We have introduced the order, however, chiefly for the purpose of recommending gardeners 
to try some of the beautiful Cape species of Polfgala against conservative walls, 
ecis 
