IOWA ACADEMY OF SCIENCES. 151 



The long red stigmas present a striking contrast. The stamens 

 are also red. The scales are reddish and long-villous. Only 

 about one third of the capsules on the Johnson county speci- 

 men are developed, the remainder being apparently unfertil- 

 ized. 



Lake Edwards, Hancock Co. 9. Shimek, S. U, 1.; Johnson Co. 36. Shimek, S. U. 1. 

 XII. SALIX CORDATA MUHL. 



Salix cordata Muhl. Neue Schrift. Gas. Nat. Fr. Berlin. 

 4:236. pi. 6. /. 3. 1806. 



The heart-leaved willow is widely distributed and is more 

 variable than any other species inhabiting the state. Notwith- 

 standing the fact that two species {S. glaucophylla Bebb, and 

 S. Missouriensis Bebb) have been cut out from S. cordata within 

 the last ten years, there remains enough variety of form to 

 render identification difficult. How much of this variation 

 should be ascribed to hybridity and how much to the natural 

 results of progressing evolution in a highly plastic species, is 

 still an open question. 



This species is a shrub of some ten or twelve feet in height, 

 growing in wet soils and along river banks. A glance at the 

 map will show that it is quite thoroughly distributed over Iowa. 

 The rather stout young twigs are yellow, but this color grad- 

 ually gives place to red-purple or brownish pubescent toward 

 the tips. The young leaves are generally densely pubescent. 

 The mature leaves are glabrous, or somewhat pubescent along 

 the midrib, oblong or oblong-lanceolate, two aind one-half to 

 four inches long, one-half to one inch wide, acute at the tip, 

 narrowed to rounded or cordate at the base, more or less glau- 

 cous below, thick and firm. Petioles are from three to six 

 lines or more. The stipules are variable in size and shape, 

 ovate-lanceolate or semilunate to reniform or oblong, very 

 small to one-half inch long. 



Staminate aments one to one and one-h^lf inches long, one- 

 half inch wide or less. Filaments in many of the flowers were 

 adnate for about half their length in specimens from Little 

 Rock (Ball Bros.), Ames (Williams), and another bearing no 

 label. The aments of both sexes are bracted at the base. 

 Pistillate aments are from one and one-half to two and one- 

 half inches long. The capsules are greenish when young, 

 becoming lighter when mature, and having a length of from 

 two to three and one-half lines. Pedicels one line or more. 



