- APPENDIX. : 495 
often transformed into deserts. Is it, therefore, remarkable that a plant 
introduced from Japan into Europe, exposed to the influences of this 
great diversity of climate, should produce imperfect sexual organs 
incapable of further propagating the plant from seeds? A rich soil, with 
the necessary amount of moisture, will never engender double flowers.” 
Mr. Darwin? describes a peculiar form of Gentiana Amarella, in which 
the parts of the flower were more or less replaced by compact aggrega- 
tions of purple scales in great numbers. A similar condition is, indeed, 
not uncommon in this plant, and, as Mr. Darwin also remarked, on 
hard, dry, bare, chalky banks, thus bearing out the views expressed by 
the writer in the ‘Gartenzeitung’ just cited. Some double flowers of 
Potentilla reptans found growing wild near York, and transmitted to the 
writer by a correspondent, were observed growing along a high wall, 
in a dry border, close to a beaten path, bordering on a gravel pit, 
others were found on a raised bank, which, from its elevation and expo- 
sure to the sun, was particularly dry. 
On the other hand, the double-flowered Cardamine pratensis, which is 
occasionally found in a wild state, always grows in very wet places. 
Of late years a remarkable double-flowered race of Primula sinensis 
has been obtained. In particular, Messrs. Windebank and Kingsbury, 
of Southampton, have succeeded in raising a set of plants in which the 
flowers are very double and very attractive in a florist’s point of view. 
The corollas in these flowers are not merely duplicated, but from their 
inner surface spring, in some cases, funnel-shaped or tubular petals 
(p. 315), so regular in form as quite to resemblea perfect corolla. These 
tubes are attached to the inner side of the tube of the corolla, in the 
same way as are the stamens, these latter organs being, it appears, 
absent. The carpels are present, but open at the top, and bear nume- 
rous ovules, hence it was at first surmised that these plants were 
obtained and perpetuated, by the application of pollen from single 
flowers to these double-flowered varieties. 
The raisers of this fine race however assert that “the double kinds 
are all raised from the seed obtained from single flowers; the double 
blooms do not produce seed, as a rule, and even if they did yield seed, 
and it were to germinate, the plants so raised would simply produce 
single flowers.” Semi-double flowers will produce seed, but it is neces- 
sary that they should be fertilised with the pollen from the single 
blooms. They rarely, however, if ever, produce really double flowers 
when so fertilised, and the number of semi-double flowers, even, is 
always small, the remainder, and, consequently, the larger part, 
proving single. To obtain double varieties, the raiser fertilises certain 
fine and striking single flowers, with the pollen of other equally fine 
1 Otto’s ‘ Gartenzeitung,’ 1866. 
2 «Gard. Chron.,’ 1843, p. 628. 
