THE PERIWINKLE FAMILY. 1 87 



villea, and Dipladetiia. Almost all the species are highly 

 poisonous. These plants are nearly all very beautiful, bearing 

 large brightly-coloured tubular flowers, having a broad five- 

 lobed limb, and they are principally found in the tropics of 

 both hemispheres, our native Periwinkles being the most 

 northern representatives. These plants very rarely bear fruit 

 in cultivation, notwithstanding Lindley's assertion (see ' Veg. 

 King.,' p. 599) that the pollen is "immediately applied to the 

 stigma." I believe it will be found that insect agency is 

 requisite in a state of nature to secure fertility, and artificial 

 fertilisation is necessary in order to secure seeds of this group 

 in cultivation. The style is constructed in a peculiar manner, 

 and, like the same organ in Lobeliads and Composites, seems 

 intended to brush the pollen from the anthers for the benefit 

 of other flowers. Nearly all the species are readily increased 

 from cuttings of the young growth, or by sowing the seeds in 

 a gentle bottom-heat of 70 to 75 ; and the more delicate 

 varieties of Dipladetiia and Allamanda may be grafted on the 

 more robust species of their respective kinds as a stock, inarch- 

 ing or splice-grafting being best. It would be interesting to 

 know whether Dipladenia, Echites, and Mandevillea can be inter- 

 grafted or hybridised with each other in any way. 



Allamanda. A showy genus of tropical stove climbers or 

 trailers, natives of South America, and represented in our 

 gardens by six or eight species, all of great beauty. A. 

 cathartica was the first species introduced to our gardens, this 

 vigorous-habited species having been brought from Guiana 

 in 1785 (see 'Bot. Mag.,' t. 388). A. Schottii, A. grandiflora, 

 A. Hendersonii (A. Wardleana), and A. nob ills are the best ; 

 and are readily propagated by cuttings of the young wood 

 inserted in moist soil, and plunged in a genial bottom-heat 

 of 75 to 80, either in a close frame or under a bell-glass, 

 as the leaves soon droop if left exposed to the atmosphere. 

 The four kinds just named are sometimes grafted on young 

 plants (struck from cuttings) of A. neriifolia, A. cathartica, 

 or its ally A. Aubletii, and are said -to bloom more pro- 

 fusely when so treated. The operation is best performed in 

 the spring under a close propagating case. I have never 

 seen seeds produced ; but this is doubtless owing to their 

 requiring artificial fertilisation when in the cultivated state. 

 They might doubtless be improved by judicious hybridisation. 

 Allamanda Hendersonii : this is a distinct-habited plant of 

 garden origin, and is supposed to be the result of a cross 

 between A. cathartica and A. Schottii (see- ' Proceedings Royal 

 Hort. Soc.,' iv.) A double-flowered Allamanda cathartica was 



