1923) REHDER, COLLECTION OF THE ARNOLD ARBORETUM 111 



f. Gregoryana Nash {Abies excelsa var. Gregoryana Gord.), but differs in 

 its more horizontally spreading branches and pendulous branchlets, 

 forming a looser and straggling bush, in its longer branchlets and longer, 

 flatter, rather distant leaves not radially arranged. 



Picea Abies f. erythrocarpa, comb. nov. 



P. excelsa var. erythrocarpa Purkyne in AUg. Forst. & Jagdzeit. LIU. 1, tab. 



(1877).— Willkomm, Forst]. Fl. ed. 2, 74 (1877).— Voss, Vilmorin's Blumen- 



gaert. i. 1241 (1895), as forma. 

 P. vulgaris var- erythrocarpa Jacobasch in Sitzber. Bot. Ver. Prov. Brandenb. 



xxiv. 98 (1882).— Beck, Fl. Nieder-Oester. 7 (1890). 

 P. excelsa a. vulgaris f . erythrocarpa Wittrock apud Schroeter in Vierteljahrschr. 



Naturf. Ges. Zuerich, xliij. 250 (1898). 

 Pinus Abies f. erythrocarpa Voss in Putlitz & Meyer, Landlex. iv. 770 (1913). 



According to the color of the young cones two forms can be distinguished, 

 one with green cones f. chlorocarpa (Purk.) Th. Fries, and one with violet- 

 purple cones, f. erythrocarpa. Both forms are found throughout the range 

 of the species and it seems impossible to determine which of the two 

 should be considered the type of the species, therefore both names must 

 be considered of equal standing. 



xPopulus canadensis Moench,Verz. Baume & Strauch. Weissenstein,81 

 (1785).— Ascherson, Fl. Prov. Brandenb. I. 646 (1864) — Koehne, Deut- 

 sch. Dendr. 81 (1893).— Mathieu, Fl. Forest. 495 (1897).—- Ascherson 

 & Graebner, Syn. Mitteleur. Fl. IV. 34 (1908). 



? P. helvetica Poederle, Man. de l'Arb. n. 148 (1792). 



P. latifolia Moench, Meth. 338 (1794). 



P. nigra b. P. helvetica Poiret, Encycl. Meth. v. 234 (1804). 



P. deltoides Schneider, 111. Handb. Laubholzk. i. 7, fig. 1 d-f, 3 o-p, 9 g-m (1904), 

 non Marshall. 



P. pseudocanadensis Schneider, 1. c. 8 (1904). 



Moench 's Populus canadensis is apparently the oldest name for the 

 hybrid between P. nigra L. and P. balsamifera L. (P. deltoidea Marsh.). 1 

 Though the original description is very meagre, the chief character, the 

 absence of the glands at the base of the blade given by Moench to dis- 

 tinguish P. canadensis from P. caroliniensis (P. balsamifera L.) is precisely 

 the character by which the leaves of this hybrid differ from those of P. 

 balsamifera. A number of varieties more or less differing in minor char- 

 acters have arisen in cultivation. 



X P. canadensis var. serotina, comb. nov. 



P. serotina Hartig, Naturgesdi. Forst]. Culturpfl. 437 (1851).— Henry in Elwes 

 & Henry, Trees Great Brit. Irel. vn. 1816, t. 409, fig. 16 (1913). 



P. angulata a. serotina Dippel, Handb. Laubholzk n. 202 (1S92).— Koehno, 

 Deutsch. Dendr. 82 (1893). 



This variety which seems to have originated in France about the middle 

 of the eighteenth century is probably the type of P. canadensis. It is 



1 Henry (in Elwes & Henry, Trees Great Brit. Irel. vn. 1807, footnote) says that the 

 identity of P. canadensis Moench is doubtful and that it is possibly the same as P. 

 angulata Aiton, but the fact that Moench particularly emphasizes its hardiness as 

 compared with his P. heterophylla which he describes as tender, does not sustain Henry's 

 suggestion. I am, however, inclined to believe that Moench 's P. heterophylla which 

 certainly is not P. heterophylla L. is identical with P. angiduta Ait. 



