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 15 35 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 

 r 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 



