CISTACEÆ. 333 
Halimium, which consists of species, some allied to the Helianthe- 
mums and others to the Cistus, and which are a connecting link 
between the two genera, the embryo is often disposed like that of 
the latter, although the gynæceum is formed of three carpels. The 
Helianthemums are herbaceous or suffrutescent plants, with opposite 
or alternate leaves, stipulate or exstipu- 
late inhabiting Europe, the Mediter- 
ranean region and Western Asia, the 
Tsles of the Western Coast of Africa, and 
the two Americas. Some have described 
more than a hundred species ;* others have 
reduced this number to about a quarter.’ 
They have been divided into seven or 
eight genera,’ five of which we preserve as 
subgenera or sections. ‘The flowers are 
generally yellow or white, or more rarely pink. In three or four 
species, Z1. canadense, corymbosum, and glomeratum,' the flowers are of 
two sorts, some polyandrous, and others triandrous or apelatous. In 
IT. glomeratum all the flowers are apelatous and oligandrous ; it has 
been proposed to make a genus of it, Zærioslema the name being 
derived from the stamens,* and which would serve to connect /e/?- 
anthemum proper to the other two generically lessened types which 
follow. 
Hudsonia and Lechea may be considered as reduced types of the 
Helianthemum lasiocarpum. 

Fie. 348, 
Long. sect. of seed. 
Fia. 347, 
Seed (8). 

1 Helianthemi sect. Dun., in DC., Prodr., i. 
267.— Gen. Halimium SpACH, loc. cit., 365 
(incl.: A. lasianthum, algarvense, umbellatum, 
Cistus Libanotis, rosmarinifolius). 
2 Cros considered the two exterior sepals of 
Helianthemum as being of the nature of stipules. 
In Helianthemum the want of alternation 
between the pieces of the corolla and calyx is 
generally more pronounced than in the Cistuses. 
Payer (Organog., 16) assigns the following 
position to the petals:—One before sepal 4, 
and two before each sepal 3 and 5. In con- 
sidering the side of the flower superposed to the 
last bract as anterior, there are then four 
anterior petals superposed in pairs to two sepals, 
3 and 5, and one posterior petal superposed to 
sepal 4.” 
3 Dun., loc. cit., 266. 
4 Spacu only admits twenty-seven. — 
Retcus., Ic. Fl. Germ., iii. t. 25-35.— WEBB, 
Phyt. Canar., t. 12 B, 13,13 B.—Botss., F1. 
Or., i. 439.—Gren. & Gopr., Fl. de Fr., i. 
167.—C, Gay, Fl. Chil., i. 202.—A. Gray, 
Man., ed. 5, 80.—Cuamp., Fl. S. Unit. St., 35. 
—Watp., Rep., i. 208; v. 58 b; Ann., i, 64; 
ii. 63; iv. 231; vii. 205. 
5 Especially Æuhelianthemum, which is dis- 
tinguished by an orthoplocate embryo, Zw- 
beraria Dun. (H. guttatum), and Rhodax, 
Spacu, which have one, a circumflex embryo, 
the other diplecolobed. 
6 Type of the genus Heteremeris, SPAOKH, loc. 
cit., 270. 
7 Span, Loc. cit., 374. 
8 They have a linear spathulate filament and a 
suborbicular adnate very small anther. In 
Fumana section of the genus Helianthemum 
(Dux., loc. cit., 274), of which a distinct genus 
has also been made (Spacu, Loc, cit., 359, t. 16); 
—Expz., Gen., n. 5027), the exterior stamens 
are sterile and moniliform. The ovules are not 
orthotropous, but incompletely anatropous, as 
in some other species of the group. (“ Nobis 
erit subgen. Helianthemi.” B. H., loc. cit., 
114.) 
