82 HERBACEOUS PLANTS 



Catkin-bearing trees, or Amentaceae, comprise Nos. 163-169. 

 Ord. 163. PLATANACEAE. Planes. 

 Ord. 165. JUGLANDACEAE. Walnuts. 



Ord. 1 66. MYRICACEAE. Sweet Gale ; Bog Myrtle, Myrica gale, is 

 abundant in Scotland and on the northern moors of England. 



Ord. 167. CASUARINACEAE. Australian trees in Conservatory No. 4. 

 ~ , ,. (Fagaceae. Oaks, Beeches, and Chestnuts. ^ Cf. the 



CUPULIFERAE. I Cor y leae ' Hazels and Hornbeams. I chapter on 



' \Betuleae. Alders and Birches. ) Trees. 



Ord. 169. SALICACEAE or Willows have a bed in this plot 

 just under the S. European Hornbeam, Ostrya carpinifolia 

 (Coryleae\ and have already been described on p. 49. The 

 Poplars are better out of the Garden. 



Ord. 171. EMPETRACEAE. The Crowberry, Empetrum nigrum, is a 

 heath-like shrub. 



MONOCOTYLEDONS 



The two plots on the west side of the Garden are laid out 

 so as to illustrate the Hardy Herbaceous Monocotyledonous 

 Plants. 



For a long time the Monocotyledons were regarded as being 

 more primitive than the Dicotyledons, but recently a view 

 has been expressed that they have been derived from 

 Dicotyledonous plants, by degeneration consequent upon 

 having lived originally in water in warm countries, so that 

 they cannot now, as land plants, recover to the full the power 

 necessary to construct such tissues as are found in Dicotyledons 

 capable of resisting the injurious effects of cold climates.* 



Consequently it is in the Palm Houses that the finest and 

 most typical examples must be sought ; and in comparison with 

 these, the out-of-door plants appear as starvelings. 



Ord. 173. HYDROCHARIDEAE. Water-plants originally confined in 

 Britain to East Anglia, but one species, Elodea {Anacharis) canadensis^ 

 invaded the waterways of this country about 1847, an d ls now one f our 

 commonest weeds in canals and ponds. Vallisncria spiralis of S. Europe 

 has a considerable sale among amateurs of fresh-water aquaria. The male 

 flowers break loose and float about, thus effecting the fertilisation of the 



* Henslow, "Annals of Botany," xxv. p. 720. 



