Penstemon xylus A. Nelson, Bot. Gaz. 31-32. 1902.

Freeman, Craig C., 2017, Nomenclatural novelties and notes in Penstemon (Plantaginaceae), PhytoKeys 80, pp. 33-39 : 37

Penstemon xylus A. Nelson, Bot. Gaz. 31-32. 1902.

Penstemon caespitosus var. suffruticosus A. Gray in A. Gray et al., Syn. Fl. N. Amer. 2: 270. 1878 (non Penstemon suffruticosus Douglas ex Benth.); Penstemon tusharensis N.H. Holmgren, Brittonia 31: 106. 1979, nom. illeg.

Type.

USA. Utah. Beaver, 1877, Palmer s.n. (holotype: GH, GH00091198 [GH website image)]; probable isotype: ISC, ISC-v-0000867 [JSTOR image] .

The correct name for this taxon at the rank of species has been the source of confusion. With the earlier name Penstemon suffruticosus Douglas ex Benth. blocking transfer of A. Gray’s varietal epithet suffruticosus at the rank of species, Rydberg (1901) published P. suffrutescens in an attempt to provide a substitute. However, in doing so, he flagged P. suffrutescens as a new species (sp. nov.). He also provided a brief diagnosis and cited a specimen ( USA. Colorado. Ridgway, woods, altitude 7500 ft, 20 Jun 1895, F. Tweedy 170; holotype: NY, NY00130526 [NY website image]) different from that of Gray’s type for P. caespitosus var. suffruticosus . Rydberg’s name must be considered a validly published species name-not an avowed substitute for Gray’s name. As noted by Holmgren (1979), the specimen cited by Rydberg is referable to P. crandallii , where P. suffrutescens must be placed as a synonym.

Nelson (1902) published Penstemon xylus and clearly stated it was a new name (nom. nov.) for Gray’s P. caespitosus var. suffruticosus . Nelson cited a specimen ( USA. Colorado. Sapinero, 1898, H.N. Wheeler 446 [COLO, COLO00396499 [JSTOR image], NY, NY00130556 [NY website image], RM, RM0004372 [JSTOR image]) that he believed was referable to A. Gray’s concept of P. caespitosus var. suffruticosus . However, it too is referable to P. crandallii . Holmgren (1979), believing that neither Rydberg’s nor Nelson’s name could be applied to Gray’s P. caespitosus var. suffruticosus because of the specimens cited by each author, published P. tusharensis as an avowed substitute. In spite of Nelson having cited a specimen that is not referable to P. caespitosus var. suffruticosus , P. xylus must stand as the avowed substitute for P. caespitosus var. suffruticosus at the rank of species, making P. tusharensis illegitimate and superfluous.