338 



DICOTYLEDONES. 



Order. Salicaceae (Willows). Trees with simple, scattered, 

 stipulate leaves. Dicecioiis. The flowers are arranged in simple inflor- 

 escences (spikes or racemes) which are termed catkins, and which 

 fall off as a whole after flowering ( <$ ) or after the ripening of the 

 fruit (?) (Fig. 322). The perianth is very imperfect 1 or wanting, 

 particularly in Salix (Fig. 323 o) ; the <$ -flower with 2 several 

 stamens and without any trace of a carpel (a, fr, c) : the ? -flower has 

 a free hicarpellate ovary, unilocnlar, and formed from 2 lateral car- 

 pels with 2 parietal (median) placenta; and generally oo ovules; the 

 style divides into two stigmas (d, e, f). The fruit is a two-valved 

 capsule and the very small seeds bear a tuft of hairs at the base. 

 Endosperm absent. The catkins are situated on dwarf-branches, which in 

 some species often develop before the leaves arid bear at their base only 

 scale-leaves ; in others foliage-leaves are borne beneatli the catkins. The vege- 



Fie. 323. Salix : male flowers of S. pentandra (a), S. aurlta (1), S. nibra (o); female 

 flo\vers of S. aurita (d), S. ingricans (e), S. inollissima (f). 



tative bud commences with 2 bud-scales which are united on the anterior side 

 into a scale. The capsule opens by the dorsal suture. The seed-hairs spring 

 from the funicle. 



Salix (Willow) has short-stalked, most frequently lanceolate 

 leaves and erect catkins with undivided bracts (Fig. 322). The 

 flowers are naked ; 1 (o in a-f) or 2 yellowish glands situated in 

 the median line. In the -flower generally two stamens, situated 

 laterally like the carpels in the ? -flower. Various forms are seen in 

 Fig. 323. The terminal bud of the branches often aborts regularly, the upper- 

 most lateral bud taking its place. 



Populus (Aspen, Poplar) has long-stalked, more or less round or 

 cordate leaves with drawn-out apex ; catkin pendulous ; lobed 



1 This is Eichler's view. According to Drude the perianth is absent ; at the 

 base of the bracts, a nectary or cup-like disc. Prantl holds the same view. 

 According to Pax the perianth is absent, but there is a disc cup-like, or reduced 

 to a single toothed scale. 



