200 Observation of the Origin of Varieties. 
nosa). 1 For instance, 80% is the figure given for Dian- 
thus Caryophyllus, 2 and double varieties of Campanula 
are said always to produce a certain number of single 
plants. In the case of double stocks one may reckon on 
between 50-60% double offspring according to the treat- 
ment and selection of the seed. Pot culture favors "doub- 
ling." 3 
The transformation of stamens into petals often goes 
so far that no pollen is 
formed. When this oc- 
curs the stigma of the 
double flower must be 
fertilized with the pol- 
len of a single flower 
or left to be pollinated 
by insects. The result 
is that the race gives 
rise to both forms every 
year. For instance Pa- 
paver nudicanle auran- 
tiacum plenum, the seeds 
of which give rise to 
between 40 and 60% of 
double -flowered speci- 
mens every year. It is 
the other way round 
with the double Petunia whose capsules are usually mal- 
formed ; but they develop a few stamens, with the pollen 
from which the stigmas of single flowers are dusted, 
'Ibid, 
" Seed catalogue of D. SACHS, Quedlinburg, 1890-91. (Dianthus 
Caryophyllus c. H. Margaritae, novelty 1889). 
3 CHATE, Culture pratique des Giroflecs. NOBBE, Botan. Central- 
blatt, Vol. XXXII, 1887, p. 253. 
Fig. 37. Anemone coronaria, "The 
Bride." Double on one side, single 
on the other. From the cultures of 
Messrs. E. H. KRELAGE & SON of 
Haarlem. 
