(2729) Andropogon ischaemum L., Sp. Pl.: 1047. 1 Mai 1753 [Angiosp.: Gram.], nom. cons. prop.

Typus: Herb. Burser I: 101 (UPS), typ. cons. prop.

Bothriochloa ischaemum (L.) Keng (in Contr. Biol. Lab. Sci. Soc. China, Bot. Ser. 10: 201. 1936) based on Andropogon ischaemum L. (Sp. Pl.: 1047. 1753) (Andropogoneae: Sorghinae) is a species native to southern and central Europe, northwestern Africa, northern Middle East, and central Asia from Iran to mainland China and Taiwan, and introduced in North America (Gould in Brittonia 19: 74. 1967; Bor in Rechinger, Fl. Iran. 70: 538. 1970; Fedorov, Fl. Evropeiskoi Chasti SSSR 1: 367. 1974; Tzvelev, Zlaki SSSR: 703. 1976; Clayton in Tutin & al., Fl. Eur. 5: 266. 1980; Davis, Fl. Turkey: 612. 1985; Barkworth & al. in Flora of North America Editorial Committee, Fl. N. Amer. 25: 646. 2003; Chen & al. in Wu & Raven, Fl. China 22: 608. 2006; Valdés & Scholz & al., Euro+Med Plantbase, http://www.emplantbase.org, accessed Sep 2019). It grows in dry, rocky or sandy places, steppe pastures, riverside sands and pebbles, forest glades, and sometimes in growing crops and disturbed places. Bothriochloa ischaemum is a caespitose perennial grass characterized by bearing a subdigitate inflorescence of (2–)3–15 racemes of spikelets.

Andropogon gerardi Vitman (Summa Pl. 6: 16. 1792) (Andropogoneae: Andropogoninae) is a species native to the prairies, meadows and open woodlands of North America, from southern Canada to Mexico (Hitchcock, Man. Grasses U.S., ed. 2: 757. 1951; Clayton, l.c.; McVaugh, Fl. Novo‐Galiciana 14: 48. 1983; Barkworth & al., l.c.: 653). It was published by Vitman (l.c.) on the basis of a species described and illustrated by Gérard (Fl. Gallo‐Prov.: 107, fig. 4. 1761), who did not adopt binomial nomenclature. Gérard stated that it originated in southern France, but its presence in that country is currently considered doubtful, since it is only based on old collections and has not been confirmed since (Tison & de Foucault, Fl. Gall.: 207. 2014). Andropogon gerardi is a tufted perennial grass, often glaucous, with 3–6 racemes of spikelets.

Bothriochloa ischaemum and A. gerardi are two clearly different species that are placed not only in different genera but in ones assigned to different subtribes within the tribe Andropogoneae; thus, no one will be surprised that there had been no confusion in the treatment they have received in the taxonomic literature. Bothriochloa ischaemum, as such, has been consistently and widely accepted over time (Keng, l.c.; Gould, l.c.: 74; Fedorov, l.c.; Tzvelev, l.c.; Davis, l.c.; Barkworth & al., l.c.: 646; Valdés & Scholz & al., l.c.), or much more rarely under Dichanthium Willemet (in Ann. Bot. (Usteri) 18: 11. 1796) as D. ischaemum (L.) Roberty (in Boissiera 9: 160. 1960) (Clayton, l.c.). Andropogon gerardi has also been widely and consistently used in the taxonomic literature (Hitchcock, l.c.; Gould, l.c.: 72; McVaugh, l.c.; Barkworth & al., l.c.: 653) under Andropogon L.

The lectotype for Andropogon ischaemum (LINN 1211.26 image!, marked “11 Ischaemum”), designated by Marchi & Longi‐Wagner (in Bol. Inst. Bioci. Univ. Fed. Rio Grande do Sul 57: 41. 1998), is actually a specimen of A. gerardi, as was noted first by Hitchcock (in Contr. U.S. Natl. Herb. 12: 126. 1908), who, identifying it as A. furcatus Muhl. ex Willd., a synonym of A. gerardi (cf. Hitchcock, Man. Grasses U.S., ed. 2: 812–813. 1951; Zuloaga & al. in Contr. U.S. Natl. Herb. 46: 32. 2003), stated that it “should not be taken as the type of the species, since it is not the plant that Linnaeus describes”, and also later by Fernald & Schubert (in Rhodora 50: 154–155. 1948), who wrote: “The plant which Linnaeus labeled ‘11 Ischaemum’ is A. Gerardi Vitm., native in North America and cultivated and probably escaped in southern France. A. ischaemum, as described and generally understood, is a wholly different species, native to central and southeastern Europe, Asia and Africa and is the plant to which all the references cited by Linnaeus apply.” As noted by Jarvis in The Linnaean Plant Name Typification Project website (https://www.nhm.ac.uk/our‐science/data/linnaean‐typification/, accessed Sep 2019), being unaware of this earlier typification, Scholz (in Taxon 49: 245. 2000) chose another type for Andropogon ischaemum (Herb. Burser I: 101, UPS image!). The identity of the specimen chosen by Scholz (l.c.) corresponds to Bothriochloa ischaemum, but obviously has not priority over that designated by Marchi & Longi‐Wagner (l.c.). After reviewing the specimens discussed above, we agree with the assessment of Fernald & Schubert (l.c.) and confirm that the specimen designated as type by Scholz (l.c.) is Bothriochloa ischaemum.

There are no formal grounds for rejecting Marchi & Longi‐Wagner's selection of a lectotype of A. ischaemum as Linnaeus's brief nomen specificum legitimum could well apply to it, and, moreover, the annotation “11” indicates that it is original material. Consequently, A. ischaemum becomes the correct name for the species currently known as A. gerardi and, therefore, falls under the provisions of Art. 57.1 of the ICN (Turland & al. in Regnum Veg. 159. 2018) and requires to be considered either for rejection or for conservation under Art. 14.1 as suggested by Jarvis (l.c.). Given the broad and consistent application of both names to these two rather different species native to two different geographical areas, the strict application of the rules would cause enormous confusion. In order to preserve nomenclatural stability and the current usage of the widely used Bothriochloa ischaemum in accordance with ICN Art. 14.1 and 14.2, we propose to conserve Andropogon ischaemum with a conserved type, the type chosen by Scholz (l.c.), a true representative of Bothriochloa ischaemum.

Rejection of the present proposal would have two main undesirable consequences: (1) The name Andropogon ischaemum would have to be applied to the species widely accepted under the name Andropogon gerardi; (2) Another legitimate name would have to be found for what has been called Bothriochloa ischaemum up to now.