(3009) Proposal to conserve the name Trillium erectum (Melanthiaceae: Parideae) with a conserved type

Abstract

(3009) Trillium erectum L., Sp. Pl.: 340. 1 Mai 1753 [Angiosp.: Lil. / Melanth.], nom. cons. prop.

Typus: United States, W. North Carolina, Henderson Co., shady woods, base of Mt. Pisgah, 8 Mai 1897, Biltmore Herbarium 1135c (MO No. 147310 [barcode MO-3717726]; isotypi: NCU barcode NCU00086525, NY barcodes NY02684139 & NY02684140, US No. 331198 [barcode 03929343]), typ. cons. prop.

Trillium L. (Melanthiaceae: Parideae) consists of long-lived perennial herbs with characteristic rhizomes and is made up of about 50 species worldwide with concentrations in eastern and western North America and eastern Asia (Gates in Ann. Missouri Bot. Gard. 4: 43–92. 1917; Haga in Jap. J. Genet. 18: 168–171. 1942; Berg in Skr. Norske Vidensk.-Akad. Oslo, Mat.-Natkurvidensk. Kl. 1958(1): 1–36. 1958; Osaloo & al. in J. Pl. Res. 112: 35–49. 1999; Case & Case, Trilliums. 1997; Broyles & al. in Amer. J. Bot. 100: 1155–1161. 2013; Lampley & al. in Phytotaxa 552: 278–286. 2022; Meredith & al., Conserv. Status Trillium N. America. 2022). Trillium erectum L. is widely collected for the medicinal plant trade (see Yokosuka & Mimaki in Phytochemistry 69: 2724–2730. 2008; Hayes & al. in Phytochemistry 70: 105–113. 2009; Ur Rahman & al. in Molecules 22: 2156. 2017). The species is common in the understory of eastern North American forests and is found from southern New Brunswick, westward across southern Ontario to the Upper Peninsula of Michigan, throughout the upper Midwest and northeastern United States and south through the southern Appalachians (Case & Case in Bull. Amer. Rock Gard. Soc. 51: 162–168. 1993, l.c. 1997; Case in FNA Ed. Comm., Fl. N. Amer. N. Mexico 26: 90–117. 2002; Griffin & Barrett in Canad. J. Bot. 82: 316–321. 2004; USDA Plants Database: available at https://plants.sc.egov.usda.gov/home/plantProfile?symbol=TRER3).

Linnaeus (Sp. Pl.: 340. 1753) described Trillium erectum providing the short diagnosis “TRILLIUM flore pedunculato erecto”, and listed four synonyms: (1) “Paris foliis ternis, flore pedunculato erecto” cited from Linnaeus (Amoen. Acad. 1: 154. 1749); (2) “Solanum triphyllum brasilianum” cited from Bauhin (Prodr.: 91. 1620; Pinax: 167. 1623) and with the annotation “Burs. IX: 12”; (3) “Solanum triphyllum canadense” cited from Cornut (Canad. Pl.: 166, t. 167. 1635); and (4) “Solano congener triphyllum canadense” cited from Morison (Pl. Hist. Univ. 3: 532, sect. 13, t. 3, fig. 7. 1699). The protologue includes as the geographical locality “Habitat in Virginia”. Both the synonyms from Cornut (l.c.) and Morison (l.c.) include illustrations that are, therefore, original material for the name Trillium erectum.

Reveal (in Phytologia 72: 2. 1992) designated as the lectotype the illustration “Solanum triphyllum Canadense” published by Cornut (l.c.: t. 167), and this lectotypification was supported by Jarvis (Order out of Chaos: 123, 901. 2007). Of all the material cited by Linnaeus, this illustration most closely reflects the current application of the name Trillium erectum, but is not without conflict with the current use of the name. The pedicel is much longer than the leaves, and the bulbous root is not characteristic of the species.

However, for lectotypification purposes, a syntype, i.e., a specimen cited in the protologue (Art. 9.6 of the ICN, Turland & al. in Regnum Veg. 159. 2018), has precedence over a cited illustration (Art. 9.12). The Burser specimen, Burs. IX: 12 (UPS-BURSER), cited by Linnaeus in the protologue, is therefore the obligate lectotype of Trillium erectum.

The sheet preserved in the Burser Herbarium (IX: 12 UPS-BURSER) bears a plant with leaves and flower, and a handwritten label, annotated as “Solanum triphyllon Brasilianum | Bauh. | Ex Gallia nova Lutetiam attulit | pharmacopaeus quidam. | 12” (see Juel in Nova Acta Regiae Soc. Upsal., ser. 4, 5(7): 62. 1923). Unfortunately, a careful examination of this specimen has shown that it does not correspond to the current concept of this species and does not support the usage of the name Trillium erectum as currently applied. Reveal (l.c.) mentioned that the Burser specimen examined by Linnaeus “(Herb. Burser III: 12, UPS)” [IX: 12] is T. grandiflorum (Michx.) Salisb. This identification had already been indicated by Juel (l.c. 1923) “Burs:s Exemplar hat zwar breite, rhombische Blätter, wie T. erectum L., die Blumenblätter sind aber oberhalb der Mitte am breitesten, und die Griffel sind ziemlich gerade, ich halte es daher für T. grandiflorum Salisb. (Burser's specimen has broad, rhombic leaves like T. erectum L., but the petals are widest above the middle and the styles are fairly straight, so I think it is T. grandiflorum Salisb.).

Linnaeus acquired a specimen, now preserved at LINN (Herb. Linnaeus No. 469.2), from Kalm, as identified by the letter “K” written by Linnaeus centrally near the bottom edge of the specimen (see Juel in Svenska Linné-Sällsk. Årsskr. 3: 61–79. 1920; Juel & Harshberger in Proc. Acad. Nat. Sci. Philadelphia 81: 297–303. 1929; Jarvis, l.c.: 215). This specimen is part of the original material used by Linnaeus to describe Trillium erectum. However, according to Reveal (l.c.) this specimen can be identified as a flowerless specimen of Medeola virginiana L. with numerous pedicels in early fruiting stages (image available at https://linnean-online.org/4162/).

In conclusion, of the original material, only the illustration in Cornut (l.c.: t. 167) matches the traditional concept and current use of the name Trillium erectum, but Reveal's lectotypification on this illustration violates Art. 9.12 and thus is not to be followed (Art. 9.19). According to Art. 9.12, the lectotype of the name T. erectum must be the syntype cited by Linnaeus in the protologue, the specimen at UPS-BURSER, but a lectotypification using this specimen would be undesirable in terms of nomenclatural stability, since it conflicts with the current application of the name. To support the continued and well-established use of the name Trillium erectum, we suggest to conserve the name with a conserved type under Art. 14.9 of the ICN.

Therefore, we here propose the well-preserved specimen at MO (No. 147310, with barcode MO-3717726) as the conserved type of Trillium erectum. This specimen shows diagnostic characters of this species (e.g., leaves broadly rhombic, about as wide as long, narrowed with nearly straight margins from near the middle to the acute base; peduncle 3–8 cm, up to ca. twice as long as the sepal; sepal lanceolate to lance-ovate or seldom ovate, flat or weakly sulcate-tipped, equalling or somewhat shorter than the petal; petal lanceolate to lance-ovate or seldom ovate, 2.5–6 cm, acute, widely spreading from the base; stamens shorter to somewhat longer than the ovary, the filaments mostly a fourth to half as long as the anthers), and clearly represents the current application of the name (e.g., Case & Case, l.c. 1993, 1997; Broyles & al. in J. Heredity 88: 325–329. 1997; Irwin in Amer. J. Bot. 87: 205–214. 2000; Case, l.c.; Meredith & al., l.c.). Rejection of the present proposal would have a very undesirable consequence because the name T. grandiflorum would have to be replaced by T. erectum, and a new name should be proposed to name what until today is known as T. erectum. Both T. erectum and T. grandiflorum have been in widespread and continuous usage since they were published in 1753 and 1805, respectively.