78 JOURNAL OF THE ARNOLS ARBORETUM [vol. hi 



110. S. delnortensis Schneider in this Jour. 1. 96. 



Sect. XXIII. Sitchenses Bebb. — See Schneider in this Jour. i. 91. 



111. S. sitchensis Sanson. — See Schneider in this Jour. i. 92. 



112. S. Coulteri Andersson. — See Schneider in this Jour. i. 93. 

 112b. S. Coulteri f. parvifolia — See Schneider in this Jour. i. 95. 



Species sectionis incertae. 



113. S. arbusculoides Andersson. — See Schneider in this Jour. u. 84 

 (1920). 



113b. S, arbusculoides var. glabra Andersson. — See Schneider in this 

 Jour. ii. 87. 



114. S. argyrocarpa Anderson. — See Schneider in this Jour. n. 88. 



115. S. cana Martens & Galeotti. — See Schneider in Bot. Gaz. lxv. 



38. 



116. S. Endlichii Von Seemen. — See Schneider in Bot. Gaz. lxv. 39 



I have not been able to find the type of this species in the herbarium at 

 Berlein-Dahlem where it should be preserved. 

 Berlin-Dahlem, March, 1921. 



b. SOME REMARKS ON THE HYBRIDS HITHERTO OBSERVED 



AMONG THE AMERICAN WILLOWS 



>een 



careful study of the forms which should be regarded as of hybrid origin. 

 Nevertheless I wish to give an alphabetical enumeration of what has 

 been mentioned in literature, and of those hybrids which according to 

 my own observations seem to occur. I have to express my best thanks 

 to Mr. A. Topffer, the famous salicologist, at Munich, who has been 

 kind in helping me compile for my personal use a list of the publications 

 referring to such hybrids. 



S. adenophylla x S. cordata. In 1880, Bebb had already collected and 

 distributed specimens of this hybrid under no. 60 of his Herb. Salic. Am. 

 It is first mentioned in Britton & Brown, 111. Fl. in. 504 (1898). 



? S. alaxends X S. Scoideriana. A specimen which might be of this 

 origin was collected by J. Macoun on June 22, 1902, in Yukon Territory, 

 Hunker Creek (No. 54387, 0.). 



S. alba [subsp.] — S. Pameachiana Andersson in K. Svensk. Vet.-Akad. 

 Handl. vi. 48. (Monog. Salic.) 1867). — S. alba y Pameachiana Andersson 

 in De Candolle, Prodr. xvi\ 212 (1808).— According to Bebb in Gard. & 

 Forest vm. 423, fig. 57 (1895), Andersson's S. Pameachiana represents a 

 hybrid between S. alba and S. lucida, and it is not identical with S. pam- 

 eachiana Barratt (not "Borr." as Andersson writes). Barratt's plant of 

 which I do not know the type may belong to S. alba var. vitellina (as 

 Carey said in Gray, Man. 428 [1848] or to S. fragilis, an opinion first 

 held by Andersson in Proc. Am. Acad. Sci. iv. 55 (Sal. Bor.-Am. 9) (1858). 



