4. Ostrya knowltonii Coville

Garden and Forest 7: 114 (Coville 1894). – O. carpinifolia f. knowltonii (Coville) Schelle, Handbuch der Laubholzbenennung: 49 (Beissner et al. 1903). – Type: USA, Arizona, Yavapai Co., Grand Canon of the Colorado River, 10 Jul. 1892, J.W. Toumey 272 (holo-: US 00130392!; iso-: A00263686!).

O. baileyi Rose, Contributions from the United States National Herbarium 8 (4): 293 (Rose 1905). – Type: USA, Texas, Guadalupe Mountains, 19 Aug. 1901, V. Bailey 435 (holo-: US 00089317!).

O. chisosensis Correll, Wrightia 3 (7): 128 (Correll 1965). – O. knowltonii subsp. chisosensis (Correll) A.E.Murray, Kalmia 12: 22 (Murray 1982). – O. knowltonii var. chisosensis (Correll) A.E.Murray, Kalmia 13: 10 (Murray 1983). – Ostrya virginiana var. chisosensis (Correll) Henrickson ex A.M.Powell, Trees and Shrubs of the Trans-Pecos and Adjacent Areas: 75 (Powell 1998). – Type: USA, Texas, Brewster Co., Chisos Mts, Big Bend NP, base of north-facing ledges, Emory Peak, 17 Jun. 1964, D.S. Correll 29733 (holo-: LL00370396!; iso-: C10009751!, GH00033786!, LL00370395!, MEXU00122440!, MEXU00711117!, MICH1192171!, NCU00000363!, TEX, US 00089316!). – Additional type material: USA, Texas, high shady crevice in rock bluff, near Nail place, Chisos Mts., 21 Aug. 1915, M.S. Young s.n. (para-: SRSC3716!, TEX00378112); ibid., north of Crown Mt, Chisos Mts, 1 Jul. 1937, B.H. Warnock 21633 (para-: SRSC3715!, SRSC3721!, TEX00378110); ibid., igneous soil on Emory-Boot trail, Big Bend NP, Chisos Mts, 7500 ft, 8 Jun. 1952, B.H. Warnock 10478 (para-: LL00378111, SRSC3718!); ibid., along a trail from Boot Spring and Basin, Chisos Mts, north side of emory Peak, Big Bend NP, 15 Jul. 1955, B.H. Warnock 12726 (para-: LL00378109, SRSC3714!). – Note: Ostrya chisosensis was recognized in Flora of North America (Furlow 1997). However, its taxonomic status has been challenged recently (McCauley & Paces 2015).