THE ASTER FAMILY. 251 



between that date and 1814, when, on the return of peace, the 

 improved flower created a great sensation among English visi- 

 tors to Paris, which led to large importations of the root during 

 the ensuing winter. Lady Holland sent seeds, not roots, from 

 Madrid in May 1804. The first plant flowered at Holland 

 House in September following, and was figured in Andrews's 

 ' Botany.' The seeds ripened in 1805, and were generally dis- 

 tributed in 1806. The original plants at Madrid do not appear 

 to have yielded many varieties not more than three are men- 

 tioned. Humboldt, however, who found the plant growing in 

 sandy meadows 5000 feet above the sea, sent home fresh seed 

 from Mexico in 1804 to Paris and Berlin, from which the 

 numerous varieties subsequently obtained were derived. The 

 first double flower was produced at Berlin in 1809; and even so 

 late as 1818 Sabine was told of a double white, but 'doubted 

 its existence.' It is interesting to remark that De Candolle 

 expressed his opinion that we should never see a blue Dahlia, 

 on the ground that blue and yellow, being the fundamental 

 types of colour in flowers, mutually exclude each other." 



There is a race of very pretty little small-flowered or Pompon 

 varieties, and some of the small single-flowered scarlet varieties 

 are very beautiful. D. imperialis (see ' Bot. Mag.,' t. 5813), a 

 large tall-growing species, was introduced to this country about 

 1867-68, and first bloomed in the Royal Horticultural Society's 

 Gardens at Chiswick in 1869-70. Nearly all the species and 

 varieties are tuberous-rooted, and are readily propagated by 

 herbaceous cuttings, division, or by herbaceous grafting on 

 tubers of common kinds. Old tubers placed in a genial 

 bottom-heat in spring yield plenty of cuttings, which, when 

 taken off with a heel in February or March, when 4 or 5 inches 

 in length, root freely. They may be potted in any light com- 

 post, and should be plunged in a bottom-heat of 75 or 80. 

 When well rooted they should be hardened off preparatory to 

 planting out after all danger from frost is over. Grafting is 

 useful where it is desirable to give seedlings or delicate varie- 

 ties a good start by working them on a rooted piece of the 

 tuber of some common variety. A slice of the fleshy bark is 

 taken off each side of the cutting-like scion or graft, and a 

 corresponding slit or cleft having been made in the stock, the 

 two are fitted together as shown in the illustration on next page ; 

 and, after being firmly bound, the two are potted in warm soil, 

 and plunged in a gentle bottom-heat, until a union is effected. 

 The lower point or heel of the scion is left exposed, and not 

 unfrequently emits roots itself, after a union with the stock has 

 been effected. D. imperialis was grafted by the late Mr 



