CHAP, ..] ClSTINEiE. 277 



size of the embryo enclosed in it, and the 

 curious manner in which it is curled up. The 

 embryo is the germ of the future plant, and it 

 is usually buried in a great mass of albumen, or 

 floury matter intended for the nourishment of 

 the young plant, till its roots are in a fit state 

 to supply it with nourishment. In the seed of 

 the Cistus, there is scarcely any albumen ; but 

 in its stead a long narrow embryo, coiled up like 

 a sleeping snake. 



The Gum-Cistus is generally called, in the 

 nurseries, Cistus ladaniferus ; but it differs ma- 

 terially from the plant so named by Linnaeus, 

 as that has a ten-celled capsule, while the cap- 

 sule of the common Gum-Cistus (which botanists 

 call C. Cyperius) has only five cells. The leaves 

 also diff'er, the under surface of those of the 

 one kind being woolly, and of the other smooth; 

 the one is also a native of Spain and Portugal, 

 and the other, as the specific name imports, of 

 Cyprus. Both species, and also C. Ledon^ 

 exude from their stems and leaves, a kind of 

 gum or resin called Ladanum or Labdanum, 

 which is used in medicine. It is from this gum 

 having been formerly always mixed with opium 

 when that drug was dissolved in spirits of wine, 

 that the name of laudanum is given to the tinc- 

 ture of opium. 



The two genera, Cistus and Hehanthemum. 



