310 ODOROGRAPHIA. 



result being that it yielded 0'91 per cent, of a golden coloured oil, 

 " of a delicate, penetrating odour of ambergris, and of sp. gr. 

 1-011 at 15^ C* Of course it is impossible to know from which 

 of the many species of Cistus this parcel was derived, and it is 

 highly probable that the fragrance of the different species varies. 



One of the most beautiful of the rosy-flowered species is C. 

 vagi n at US, a native of Teneriffe. Its hairy leaves are lance-shaped, 

 three-nerved, and dilated towards the base, while the splendid large 

 rose-coloured flowers are very numerous and in terminal panicles. 

 The petals are crumpled and have wavy margins, bent inwards, 

 with a yellow spot at the base. 



C. populifolius is a very distinct species of large stature, 

 with ovate-cordate, acuminate, rugose leaves on long petioles; it bears 

 lateral cymes of medium-sized white flowers tinged with yellow at 

 the base of the petals ; the sepals are acuminate and clammy. 

 The pubescence on this plant is slighter than in many of the other 

 species, but viscous. 



One of the hardiest species in cultivation is C. laurifolius ; its 

 leaves are petiolate, 3-nerved, ovate-lanceolate, viscous, and densely 

 tomentose beneath. The flowers are white. This forms a robust 

 shrub 6 or 7 feet in height. 



A large number of species are in cultivation, and they would be 

 more extensively cultivated if they were better known. Many of 

 the species will survive through the winter in England in the 

 open air, if the weather be not very severe. They will succeed in 

 any common soil, or a mixture of loam and peat will suit them 

 very well. They may be increased by layers ; or young ripened 

 cuttings, taken off at a joint, in July or August, and thinly planted 

 under a hand-glass, will root readily. They may also be raised 

 from seeds, which are produced in abundance ; in this way, fair 

 sized specimens may be obtained in three years. Most species 

 thrive best in a dry soil. 



Acorus Calamus, the " Sweet Flag." 



The name Acorus is given to a genus of semi-aquatic herbaceous 

 perennials belonging to the Xatural Order Aroidece, comprising a 



* Bericht, April, 1893. 



