284 FLOWERS OF GARDEN AND GREENHOUSE 
possession of a double involucre, the lower series of which spreads. 
The disk is beset with membranous coloured scales, which are drawn 
out to a fine point, and equal or exceed the disk-floret in length. The 
leaves are pinnate. The fruits are four-angled, tapering to each end, 
crowned with two to four rigid bristles. The species are all natives of 
Mexico. Only two or three are in cultivation. 
CosMOS BIPINNATUS (twice pinnate). Stem erect, 
furrowed, with spreading branches, 2 feet high. Leaves 
opposite, pinnately divided into thread-like segments. Flower-heads, 
solitary, 2 inches across; rays reddish purple, disk pale yellow; July 
and August. Introduced 1799. 
C. DIVERSIFOLIUS (differing - leaved). A dwarf perennial with 
tuberous roots and Dahlia-like, but variable leaves. Flower-heads 
varying from blackish purple to red-purple, disk-florets and ray-florets 
of the same colour; July and August. Introduced 1862. 
C. SCABIOSOIDES (Scabious - like). Tuberous - rooted _ perennial. 
Stems downy, 3 to 4 feet high. Leaves bristly beneath; leaflets five 
lance-shaped, toothed. Flower-heads scarlet; October. Introduced 1834. 
C. TENUIFOLIUS (slender-leaved). Stems 1 to 2 feet high. Leaves 
finely-divided, Fennel-lie. Flower-heads rich dark purple ; September 
and October. Annual. 
Cosmos requires similar treatment to Dahlias. The 
annual species are grown from seed sown in gentle heat 
in March; and the perennials propagated by cuttings or divisions of 
the tubers, which are stored and started into growth precisely a 
recommended for Dahlia. 
Description of Portion of stem of Cosmos bipinnatus with leaves 
Plate 142. and flower-heads. Fig. 1 is a section through the head, 
natural size; 2,a ray-floret; 3, a disk-floret; 4, the fruit, natural size 
and enlarged; 5, a seedling. ; 
Principal Species. 
Cultivation. 
MARIGOLDS 
Natural Order Composirz, Genus Tagetes. 
TAGETES (classical, derived from Tages, an Etruscan deity). A genus 
including about twenty species of annual herbs, with pinnately divided 
(rarely simple), opposite leaves. The flower-heads are always yellow 
or orange in the natural forms, the ray-florets in a single series, 
normally five in number ; disk-florets tubular : involuere of one series 
