Trillium cernuum L., Sp. Pl. 1: 339–340. 1753

Type:— USA. In Carolina, [no collector given], 469.1 (LINN!, lectotype designated by Gleason, Bull. Torrey Bot. Club 33: 390, 1906)

Heterotypic synonyms: Trillium brevipetalum Raf., Med. Fl. 2: 100. 1830. Type:—Near the lakes, Ontario and Erie. Type not located.

Trillium glaucum Raf., Med. Fl. 2: 102. 1830. Type:— In Pennsylvania , near Philadelphia, Maryland, Virginia, “& c.”.” Type not located.

Trillium hamosum Raf., Med. Fl. 2: 101. 1830. Type:—In the Pocono Mountains, Pennsylvania, discovered by Steinhauer. Type not located.

Trillium medium Raf., Med. Fl. 2: 102. 1830. Type:—from New England south to Virginia. Type not located.

Trillium declinatum (A.Gray) Gleason, Bull. Torrey Bot. Club 33: 389. 1906. nom. illeg.

Basionym: Trillium erectum var. declinatum A.Gray, Manual [Gray], ed 5: 523. 1867. Type:— USA. 1863, Robbins s.n. (holotype,: GH 00030145 digital image!; isotypes, GH00030146 digital image!, MO-104984!) .

Notes:— Patrick annotated MO 104984 as Trillium cernuum, against which Gray (1867) compared his var. declinatum in the protologue. The name at species level is preceded by T. declinatum Raf., which is T. catesbaei, and Fernald (1932) provided the new name T. gleasonii . Patrick also annotated NY00319876(!) as lectotype but never published this. This collection, NY00319876, was annotated by Patrick as T. flexipes . This may have been one of the specimens that Gray (1867) used as part of his description of var. declinatum, but he cited only collections by Robbins from Lake Superior with no mention of additional specimens in his description of var. declinatum . Fernald (1932) later provided a new name, T. gleasonii, because T. declinatum Raf. preceded T. declinatum (A.Gray) Gleason. We here assign this concept to T. cernuum .

Trillium cernuum var. macranthum Eames & Wiegand, Rhodora 25: 191. 1923. Type:— USA. New York: Tompkins, Valley of Fall Creek, Round Marshes (Gracie’s Swamp) and vicinity, Dryden, low woods, north end of marshes, 31 May 1914, Eames & MacDaniels 2012 (holotype: GH00030148!; isotypes: CM0361 digital image!, F0046068 F digital image!, MIN1002612 digital image!, S-G-7311 digital image!).

Note:— Eames & Wiegand (1923) discussed variation in T. cernuum .

Trillium cernuum f. viride Cayoutte & Cayoutte, Naturaliste Canad. 111: 326. 1984.

Type:— CANADA: Quebec: Saguenay –Lac-Saint-Jean (Quebec), Saguenay, Ilets-Jermie, 48°53’N- 68°48’W, 12 Jul 1973, Cayouette 73-418 (holotype: not located; isotypes: DAO000466224 digital image!, CM0491 digital image!, GH00030151 digital image!, MICH1192833 digital image!, NY00319873 digital image!, US00288583 digital image!) .

Trillium cernuum f. marginatum Cayouette & Cayouette, Naturaliste Canad. 111: 326. 1984.

Type:— CANADA. Quebec: Comté de Gaspé-quest, Mont-Saint-Pierre, 49°13’ N-65°49’0. Erablière à bouléau jaune, en flanc de côteau, exposition sud-est. 13 Jun 1973, Cayouette & Quattara 73-145 (holotype ” QFA; isotypes: CM0360 digital image!, DAO000466223 digital image!, GH 00030150 digital image!, MICH1192832 digital image!, NY00319872 digital image!, US00288582 digital image!) .

Trillium cernuum f. tangerae Wherry, Bartonia 23: 49. 1945. Type:— USA. Pennsylvania: Adams County, 2 miles west-southwest of Iron Springs, moist rocky woods, 5 May 1945, Wherry s.n. (holotype: PH 00028390, lectotype designated here, digital image!; isolectotype: PH 00028389 digital image!).

Note:— Patrick annotated PH 00028390 as lectotype. We formalize this designation here .

Trillium cernuum var. terrae -novae Boivin, Rhodora 55: 101–102. 1953. Type:— CANADA. Newfoundland: west coast near Stephensville, west side of E. Harmon Air Force Base, in wet black soil under Alder bushes, 9 June 1949, Bassett 293 (holotype: DAO 000466288 digital image!).