DWARF WILLOW : BARBERRY 281 



A A Leaves sub-orbicular, or hardly 

 longer than broad. 



Salix herbacea, L. Dwarf Willow. The smallest 

 British woody plant, with few (2 3) leaves in tufts at 

 the ends of the shoots ; leaves rarely over 2 cm. long : rare 

 Northern creeper. Leaves 8 20 x 7 20 mm. (1 3 cm.), 

 oval, oblong, broad-obovate, or rounded-ovate to orbicular ; 

 obtuse or slightly retuse ; base indented, finely crenate- 

 serratulate, glabrous, green and shining on both surfaces, 

 delicate and herbaceous or papyraceous. Venation pel- 

 lucid; the reticulation prominent beneath. Stomata 

 numerous on both surfaces. Petiole very short. Stipules 

 minute, ovate or obsolete. Autumn leaves yellow. 



(ii) Leaves exstipulate. 



[See note, p. 161. The difficulty is a real one, the 

 stipules often being so minute and caducous as easily to 

 escape observation.] 



(a) Leaves spinescent-toothed ; some com- 

 pletely converted into spines. 



Berberis vulgaris, L. Barberry (Fig. 107). Armed 

 bush, with tufted spinescent-toothed leaves, and yellow 

 wood. Leaves 3 8 x 1*5 3'5 cm., obovate or oblong- 

 obovate, obtuse, attenuated below and articulated to the 

 very short petiole (5 15 mm.) : spinose-serrate or -dentate, 

 glabrous and thin, dark polished green, paler beneath. 

 Tufted on the dwarf shoots but scattered on the long 

 shoots. Dwarf shoots in the axils of simple, trifid or 

 quinate spines which are modified leaves, and may be 

 jointed and more or less laminate and membranous below, 

 the upper margins of the sheath prolonged into two 

 minute stipule-like bristles: see p. 20. The leaves are 



