Trillium rugelii Rendle

Floden, Aaron J. & Knapp, Wesley M., 2023, Typification of the North American species of Trillium subg. Trillium (Melanthiaceae: Parideae), Phytotaxa 599 (3), pp. 193-200 : 196-197

Trillium rugelii Rendle , J. Bot. 39: 331–332, pl. 426, f. B. 1901.

Type:— USA. North Carolina: on the mountains of the Broad River, Mar 1841, Rugel s.n. ( BM 327335 & BM 001009870 [one sheet] digital image!, lectotype, designated here; isolectotypes: E00346019 digital image!) .

Heterotypic synonyms: Trillium affine Rendle, J. Bot. 39: 334. 1901. Type:—USA. Georgia: s.d., Rugel s.n. (holotype: BM 000547280 digital image!)

Trillium album (Michx.) Small, Fl. S.E. US. 278. 1903. Basionym: Trillium rhomboideum var. album Michx., Fl-Bor. - Amer. 1: 215. 1803. Type:— P 00730404 digital image!, lectotype, designated here) (see also T. erectum ).

Notes:— Trillium rugelii was described in 1901 by Rendle from a Rugel collection at BM. In the protologue, he stated “Specimens in Herb. Mus. Brit.” There is one sheet at BM that has two stems, one of which was selected as a lectotype, as noted on the annotation label by Patrick (c. 1981), but this typification was never formally published. The stem on the upper left was selected as the lectotype by Patrick and the stem on the right was selected as an isolectotype despite the presence of a single collection label. The ICN rules ( ICN 8.2 ) state that this should be treated as a single gathering. Thus , we select the sheet at BM as the lectotype ( BM327335 & BM001009870 ) .

The combination T. album was made by Small (1903). The basionym was Michaux’s T. rhomboideum var. album , which was based on specimens that are in fact T. rugelii . Here, we typify the name T. rhomboideum var. album and designate the specimen at P (00730404) as the lectotype of T. rhomboideum var. album .

Notes:— Case (1997) reported differences in fragrance between the forms in the Southern Appalachians vs. plants from the middle and northern parts of Alabama. He described them as strongly fragrant of old garden roses but did not mention that of the mountain plants. Observations by AF of T. rugelii from Tennessee south to Alabama and east to South Carolina have shown that floral fragrance is variable and often similar to some forms of foamflower ( Tiarella ), fragrant violets, or Cyclamen . The intensity of the fragrance varies over the distribution, but the floral fragrance is often stronger in more southern populations.