288 DOWNY WILLOW, ETC. 



tend to form cross-ties, coming off at open angles. The 

 secondaries are very short, and leave the midrib at open 

 or nearly right angles. 



[There are several varieties, but the very narrow wavy 

 leaves, silky beneath, characterise the species. The silky 

 appressed hairs parallel to the secondaries, not to the 

 midrib, distinguish it from S. alba : see p. 244.] 



tt Leaves not more than 16 x 1 1-5 cm. 



Salix repens. The leaves may be entire, and may 

 then be classified here (see p. 243), and similarly with 

 the rare 8. Lapponum (see below). S. nigricans has 

 also occasionally narrow and entire stipulate leaves (see 

 p. 292). 



** Leaves broader, elliptic to ovate, obovate, 

 &c. 



f Leaves hoary or tomentose, and white or 

 grey beneath. Rare dwarf or alpine pros- 

 trate shrubs, with prominent and reticulate 



venation beneath. 



% 



Leaves rugose. 



Salix Lapponum, L. Downy Willow. Bare sub-alpine 

 creeper, with very variable elliptic, ovate, or oblong-elliptic 

 or obovate-lanceolate, to lanceolate leaves equally attenu- 

 ated at base and apex, tomentose below, and often above 

 also ; acute or acuminate, the margins nearly parallel in the 

 middle, entire or faintly undulate-dentate, rugose; silky 

 velvety or arachnoid when young, at length white cottony 

 beneath and dull or almost bright green or silky villous 

 above, 3*5 7 x 1 2 cm. (3 9 x 0'8 3*5 cm.) ; petiole up 

 to 1 cm. Stipules small or obsolete. No stomata on the 

 upper surface. Venation pinnate-reticulate, rather promi- 

 nent beneath. Autumn leaves yellow. 



