1921] SCHNEIDER, NOTES ON AMERICAN WILLOWS, XII. 113 



Folia satis distanter (tantum apicem versus densius) breviter denticulata, 

 dentibus vix ultra 3-4 pro 1 cm. ? anguste elliptico-lanceolata, apice 

 breviter acuminata, basi cuneata 5:1-13:2 cm. magna; petioli apice 

 nunquam glandulosi 54. S. irrorata. 



Folia circumcirca dense breviter crenato-serrata; petioli apice saepe 



glanduliferi. 

 Petioli glabri vel tantum superne in sulco pilosuli; folia ovato- vel 



elliptico-lanceolata, basi obtuse cuneata ad iotundata, apice longe 

 acuminata, 6:1.2-12:2.5 cm. magna 9. S. Bonplandiana. 



Pc tioli undique pilosuli vel folia plusminusve lineari-lanceolata, ad 

 13:1.2 cm. magna (confer etiam 12. S. Harbisonii). 



lib. S. longipcs var. venulosa. 



Stipulae distinctae. 



Forma foliorum anguste oblonga, marginibus utrinque plusminusve 

 ])arallelis, basi rotundata ad cordata, apice vix acuminata, folia ad 

 8:1.2-2 cm. magna; stipulae petiolis tantum 3-7 mm. longis sublongiores, 

 intus hand glanduliferae . . 52. *S. mexicana. 



Forma foliorum lanceolata vel anguste elliptico- vel ovato-lanceolata, 



basi acuta vel obtuse cuneata apice acuminata, folia ad ultra 11:2 cm. 



magna; stipulae petiolis ad 15 mm. longis breviores intus glanduliferae 



(confer etiam I lc. S. longipes var. Wardii) . . . . 10. S. laevigata. 



Laminae foliorum etiam adultorum utraque facie vel tantum subtus pilosae. 



Pubescentia sericea, adpressa, plusminusve argentea. 



Folia subtus fere glabra, pilis adpressis difficile recognoscendis prae- 

 dita, satis laevia, costa flavescente elevata glabra, 1.5: 0.4-9:1.8 cm. 

 magna; petioli 4-8 mm. longi . ...... . 113. S. arbusculoides. 



Folia subtus distinctius argenteo-pilosa, magis reticulata, costa plus- 

 minusve pilosula, ad 12:2.5 cm. magna; petioli ad 11 mm. longi. 



90. S. sericea. 



Pubescentia villosula, haud argentea. 



Folia lanceolata ad ovato-oblonga, majora ultra 2.5 cm. lata vel pube- 



centia tantum grisea 58. S. missouriensis. 



Folia saepissime anguste lanceolata vel anguste ovato-lanceolata, pubes- 

 centia pilis griseis fulvisque mixta vel folia matura glaberrima. 



11. S. longipes. 



Folia integerrima vel distanter (saepe obscure et satis repando-) denticulata 

 dentibus pro 1 cm. vix plus quam 2 vel petioli vix ultra 5 mm. longi et folia 

 utrinque stomatifera. 1 

 Petioli vix ultra 5 mm. longi; folia linearia ad lineari-lanceolata, subtus saepe 

 paullo discoloria, glaberrima vel pilis sparsis adpressis difficile visibilibus 

 obdita, utraque facie acqualiter stomatifera, 5:0.5 ad 13:1.2-2 cm magna. 



19. S. melanopsis. 



Petioli longiores vel folia supra medium latiora vel integerrima. 



Pubescentia (saltern foliorum novellorum) pilis griseis fulvisque mixta jramuli 



hornotini glaberrimi, fusci vel flavo-rubri. 



Folia vix ultra 6:0.8 cm. magna, integerrima. 



85c. *S. Geyeriana var. meleina. 



Folia ad 10:1 5-2 cm. magna, saepe plusminusve distanter denticulata. 



86. S. Lemmonii. 



Pubescentia tantum grisea vel ramuli novelli plusminusve dense tomentelli 

 vel pilosuli; folia saepissime supra medium latiora, magis oblanceolata, ad 

 11:2 cm. magna, plusminusve repando-denticulata .... 93. S. humilis. 



= = Laminae oblongo-ellipticae,ovatae vel ovato- vel elliptico-lanceolatae, 



vix ultra 3K(-4)plo longiores quam latae. 



: Folia integerrima vel tantum pro parte satis distanter et saepe indis- 



tincte dentata crenatave. 2 



1 See also such forms as 82b. S. Candida denudata et 104a. S. pellita psila and such 

 a critical species as the Arctic 43. S. desertorum. 



2 Leaves of more vigorous branchlets of some of these species may show a rather 

 distinct dentation but the normal leaves are entire or slightly dentate or crenate or 

 bear only a few distant teeth. 



