DAHLIAS 281 
light sandy soil was the fitting earth for them, the originals having 
been found in sandy meadows at an altitude of 5000 feet. In 1800 the 
Abbé Cavanilles, by whom the genus was created, sent specimens of 
D. coccinea to Thouin, Professor of Culture in the Muséum d'Histoire 
Naturelle at Paris. These were the first Dahlias cultivated in France, 
and they were grown for the sake of the tubers, which were, however, 
rejected alike by men and cattle. From this batch a third consignment 
came to England in 1815, and with more liberal treatment it succeeded, 
and became greatly modified by cultivation. Other species have been 
introduced in later years, and some of these have had their share in the 
production of the enormous number of varieties now included in the 
catalogues of professional growers. Among these later introductions may 
be mentioned D. excelsa, D. imperialis (1863), D. Juarezii (the Cactus 
Dahlia, which originated under cultivation in Mexico), D. Merckz (1839). 
DAHLIA COCCINEA (scarlet). Stems 3 to 4 feet high. 
Leaves pinnately divided into lance-shaped leaflets, rough. 
Flower-heads with yellow disk-florets and scarlet rays ; August to October. 
D. ExcELsA (tall). Stem becoming woody, thick and tree-like, 20 
feet and more in height. Leaves 24 feet long by 2 feet broad, divided 
into pinnate leaflets, which are themselves pinnately lobed. Flower-heads 
4 inches across, rays pale lilac-purple; late autumn. Should be grown 
in pots or tubs, to be taken into greenhouse before the first frosts. 
D. IMPERIALIS (imperial), Stems 10 to 12 feet high. Flower-heads 
white with lilac tinge, and streaks of deep red at the base of the 
ray-florets; bell-shaped and drooping, disposed in enormous panicles ; 
late autumn. Requires similar treatment to D. excelsa. 
D. Juarezii (Juarez’). Cactus Dahlia. Stems 3 feet high. Flower- 
heads brilliant scarlet; florets rayed of varying lengths, overlapping, giving 
the head an appearance quite distinct from the others. A garden form. 
D. Merck (Merck’s). Stems 2 to 4 feet high. Leaves pinnately 
divided, the leaflets pinnately lobed. Flower-heads with white or lilac 
rays and yellow disks; small, but of good form; October. Introduced 
1839. The var. Decaisneana has purple rays. 
D. VARIABILIS (variable). Stems 4 to 6 feet high. Leaves pinnately 
compound, the leaflets lobed. Flower-heads very variable in colour, the 
disk-florets yellow, the rays white, yellow, or some shade of scarlet 
August and September. By cultivation the disk-florets were turned 
into rays, producing the so-called “double” flower-heads. The original 
forms are shown in Plate 141. 
Cultivated The enormous number of garden varieties of Dahlias 
Varieties. receives many additions every year, and any selection is 
11.—30 
Principal Species. 
