Botany of tke Dahlia 23 



of the leaves, generally in pairs, and bear a single 

 flower each, although there are instances on record 

 when, occasionally, the double dark red variety has 

 borne two flowers on a peduncle. This is, however, 

 of rare occurrence. 



The primary involucre is composed of five green 

 persistent fleshy bracts, which are so much reflexed 

 that they point downwards. They are ovate or ovate- 

 lanceolate in form in the P,ompon and Show varieties, 

 but linear -lanceolate in the Cactus. The secondary 

 involucre is composed of the outer row of bracteoles 

 or palese, each ray and floret having a bracteole at 

 its base, which is equivalent to a calyx. Very few 

 species in Composite have this scale or calyx, which 

 is therefore quite a distinguishing feature of the 

 Dahlias, its more common form being that of simple 

 or branched hairs termed the pappus. These scales 

 form a protection to the young florets in the same 

 way as an ordinary calyx. The outer row is 

 generally composed of eight or nine scales, green at 

 the base, and transparent from the middle upwards. 

 The inner rows are all transparent, but some of the 

 more outward ones are slightly tinged with green. 



The Single Dahlia is, no doubt, representative of 

 the plant in its original wild state, but, by cultivation, 

 the florets are all, or nearly all, developed into rays, 

 in the double varieties. The Dahlia rays are folded 

 in a peculiar manner, the one side overlapping the 

 other. They are quite flat in bud, but assume after- 

 wards a round form, thus giving the tubular appearance 

 so characteristic of some of the varieties. This tubular 

 arrangement is best seen in the double show blooms. 

 In the single varieties the ray is folded in the same 



