1 1 6 A US TRAL1AN B TANK 



Dock. — RUMEX. (Natural Order, Polygon ace^e.) 

 Pp. 30, 42, 204. — A numerous genus, extensively dis- 

 persed, particularly in cool climates. There are about 

 eight known kinds in Australia, some of which have been 

 introduced. The roots of some species are used in medi- 

 cine, the leaves of others as a vegetable; an excellent 

 dentifrice is prepared from the powdered roots. It is 

 sometimes inaptly called ' Wild Rhubarb.'' 



Dogwood. — PROSTANTHERA LASIANTHOS. 

 (Natural Order, Labiate.) See chapter 'Australian 

 Vegetation/ p. 79. 



Doodia. — (Natural Order, Filices.) See chapter 'Aus- 

 tralian Vegetation/ p. 80. 



Dragon's Blood Tree. — DR AC. -EN A DRACO. 

 (Natural Order, Liliacks.) P. 191. — An account of a most 

 remarkable specimen of this plant — the famous Dragon 

 Tree of Teneriffe, believed to be the oldest tree in the 

 world, and destroyed during a storm in 1867 — may be 

 found in any standard work on descriptive botany. Red 

 gum, called ' Dragon's Blood,'* is obtained from this 

 Dracaena. The plant thrives remarkably well in the Mel- 

 bourne Botanic Gardens, which contain some young but 

 healthy specimens. The Dracaena Draco is not to be con- 

 fused with the Dragon's Blood Palm (Calamus Draco), which 

 also produces a red gum, used as a varnish by artists. The 

 latter plant is now included in the genus Daemonorops, and 

 the gum is obtained from its ripe fruit. Many species of 

 dwarf Dracaenas or Cordylines, with variegated and coloured 

 foliage, are cultivated in conservatories ; and there are 

 several tall-growing species common in Australian gardens, 

 such as Dracaena or Cordyline Australis, C. Forsteri, and 



