Barkworthia stillmanii (Bol.) Romasch., P.M.Peterson & Soreng, comb. nov.

Peterson, Paul M., Romaschenko, Konstantin, Soreng, Robert J. & Reyna, Jesus Valdes, 2019, A key to the North American genera of Stipeae (Poaceae, Pooideae) with descriptions and taxonomic names for species of Eriocoma, Neotrinia, Oloptum, and five new genera: Barkworthia, x Eriosella, Pseudoeriocoma, Ptilagrostiella, and Thorneochloa, PhytoKeys 126, pp. 89-125 : 92-93

Barkworthia stillmanii (Bol.) Romasch., P.M.Peterson & Soreng, comb. nov.

Stipa stillmanii Bol., Proc. Calif. Acad. Sci. 4: 169. 1872 [Basionym] ≡ Achnatherum stillmanii (Bol.) Barkworth, Phytologia 74(1): 14. 1993 - Type: USA, California, Sierra Nevada, Blue Cañon, Jul 1870, H.N. Bolander, M.D. Kellogg & co. s.n. (holotype: NY-00431576 [image!]; isotypes: GH-00017890 [image!], K-000873398 [image!], MO-3055652!, MO-3055653!, MO-3055654!, NDG-07159 [image!], US-556922!). Fig. 1A-F .

Distribution and habitat.

Barkworthia stillmanii is distributed in scattered locations in northern California (Butte, El Dorado, Nevada, Placer, Plumas, Sacramento, Shasta, Sierra, Tehama, Trinity, Tulare, and Yuba Counties) associated with yellow pine and red fir forests; 10-1500 m ( Barkworth 2007; Calflora 2018).

Comments.

In a molecular-derived phylogeny of the Stipeae using 10 DNA markers Barkworthia stillmanii is sister to a well-supported Piptatherum clade, which is strictly Old World in distribution, and has cauducous awns, and dark glossy lemmas in fruit ( Romaschenko et al. 2012).

Figures

Figure 1. Barkworthia stillmanii: A habit B ligule C panicle D glumes E floret F floret (close up). Eriocoma hymenoides: G culm and panicle H panicle branch I glumes J floret K lemma awn L floret base (callus).