Ball — Notes on Some Western Willows. 87 



Such are the leaves of the fertile twigs ; on sterile twigs still 

 attached to the fertile the leaves are fully an inch in length 

 and broad in proportion. Specimens of this extreme are not 

 numerous. 



The variety Wolfii Bebb is a small, narrow-leaved form 

 with capsules glabrate. 



The normal and most common (and what should be con- 

 sidered the typical) form of S, desertorum has oblong, ellip- 

 tical-lanceolate, or somewhat oblanceolate leaves, mostly 

 acute, broad and blunt, rarely attenuate at base, 1-1^ in. 

 long, 5-7 lines wide, nerves elevated below; aments short, 

 thick, oblong-cylindrical, very densely flowered, \-\ in. long, 

 on bracteate-leafy peduncles 3-6 lines long; scales mostly 

 tawny; capsules sessile or very short pedicelled, 2 or some- 

 times 3 lines long when mature. 



Specimens representing the normal form are as follows: — Engelmann,. 



3 and 5, 1881. —Engelmann, Rocky Mt. Fl. ( ), Colo., Ag. 30, 1874.— 



Porter, Twin Lakes, Colo., Jl. 25, 1872. — Cowen (Colo. State Agr. Coll.), 

 Fl. Colo., 8. glauca var. villoaa, Jefferson, 1896. — Baker, PL No. Colo. 

 (Rowlee), 14, &nd 17, 1896. — Brandegee, 221^ Colo. 1871; 1004, Colo. 

 1874 (both labelled S. glauca var sencea) . — Nelson, Fl. Wyo., 1759, 

 1895. — Jones, Flora Utah, 1171j 1879. 



From this normal form two lines of variation are found, 

 one including the type specimens and the var. Woljii — that 

 is, the extreme form already discussed ; the other varying in 

 the opposite direction toward S, glauca with its longer and 

 proportionately narrower, villous leaves, and longer, looser 

 aments of longer capsules. The extreme forms of this latter 

 variation occupy the doubtful ground between the two species 

 of the Rocky Mts., S. desertorum and the so-called S. glauca 

 villosa. The following list includes specimens that are for 

 the greater part to be referred to jS. desertorum but which 

 present characters more or less distinctly transitional toward 

 the accompanying forms of jS. glauca. 



Specimens examined. — Baker, Earle, and Tracy, 216, PL So. Colo., S. 

 chlorophylla, 1898. —Baker, 9*, 16, PL No. Colo. ( ), 1896. — Eogel- 



♦ Baker, No. 10, Is not a Salix but Vaccinium caespitosum Michx. A 

 small specimen of this Vaccinium is also included with Engelmann 6, S, 

 desertorum, 1881. Jones, 1571, West. FL, 1894, distributed as S. deserto- 

 rum, is composed of staminate twigs of S. lasiandra and pistillate twigs of 

 S. lasiolepis. 



