INCOMPLETE. 



345 



Comptonia asplenifolia is used in cases of diarrhoea in North America. The 

 fruit of Myrica sapida is eaten in Nepal. Genera : Myrica, Comptoma. 



BETULACEJ3 (THE BIHCH OBDEB) consists of trees or shrubs ; 

 monoecious, with both kinds of flowers in scaly catkins, achlamydeous, 

 2 or 3 under each bract (scales of the flowers whorled in Almts} ; ovary 

 2-celled, 2-ovuled, ripening into a dry, 1-celled, 1-seeded, often winged 

 nut, without a cupule ; seed pendulous, aperisperrnic ; radicle superior. 

 Illustrative Genera : Betula, L. ; Alnus, L. 



Affinities, &c. This small Order is distinguished from Cupuliferae and 

 Juglandaceae by the free ovary, and the regular occurrence of 2 carpels in 

 the ovary, one cell, however, being usually obliterated in the fruit. From 



Fig. 434. 



Fig. 435. 



Fig. 434. Male and female catkins of the Birch. 

 Fig. 435. Samaroid fruit of the Birch (Betula alba). 



Salicaceae they differ in the 2 cells, and by the solitary ovule in each cell. 

 These plants belong chiefly to temperate and cold climates ; Betula nana 

 and Alnus incana form dwarf shrubs further north than any other woody 

 plants, except some Willows. The bark is regarded as tonic and astrin- 

 gent, and an empyreumatic oil is obtained from that of the common 

 JBirches Betula alia and glutinosa, which gives the peculiar odour to 

 Russia leather. The bark of B. papyracea is used for making baskets 

 and many other articles in North America. The sap of B. alba, nigra, 

 and fatto yieldf sugar at certain seasons. Alnus glutinosa is the common 

 Alder; its wood is esteemed for work to remain under water, and for the' 

 manufacture of charcoal ; the leaves and female catkins are sometimes 

 used by dyers. 



SALICACEyE (THE WILLOW OBDEB) consists of dioecious trees or 

 shrubs, with both kinds of flowers in catkins, one flower under each bract, 

 entirely destitute of envelopes, or with a membranous cup-like perianth 

 (fig. 437, Populus) ; the fruit a 1-celled and 2-valved pod, containing 

 numerous seeds clothed with long silky down ; no perisperm j radicle 

 inferior. Illustrative Genera : Salix, L. ; Populus, L. 



Affinities, &c. This amentiferous Order, consisting of but two genera, 



