Bouteloua triaena (Sprengel) Scribner (1891: 307–308)

Sandoval-Ortega, Manuel Higinio, 2023, Taxonomy of Bouteloua juncea and Bouteloua triaena, two species confused for more than a century, Phytotaxa 612 (3), pp. 261-271 : 265-267

Bouteloua triaena (Sprengel) Scribner (1891: 307–308) .

≡ Atheropogon triaena Sprengel (1825: 293)

≡ Triaena racemosa Kunth (in Bonpland et al. 1815 [1816]: 144).

Lectotype (designated here):— MEXICO. Guanajuato: apricis inter Guanaxuato et Villalpando , 1803, Bonpland & Humboldt s.n ( BW01795010 [image!]).

= Dinebra cristata Presl (1830: 293) .

Lectotype (designated here):— MEXICO. Habitat in Mexico, s.f., Haenke s.n. ( PR203601 [image!]) Fig. 4.

= Triathera gracilis Fournier (1886: 141) .

Lectotype (designated here):— MEXICO, Cuernavaca, 1839, Berlandier 1016 ( W0026340 [image!]).

Notes on the type of Triaena racemosa :— Kunth’s descriptions from “Nova Genera et Species Plantarum” are based on the botanical collections that Humboldt and Bonpland made in America from 1799 to 1808 ( Bonpland et al. 1815 [1816], Stearn 1956). Currently, most part of the collections of Humboldt and Bonpland are deposited in P and B (HUH-Index of Botanists 2023, TL-2 2023).

In TROPICOS (2023) it is mentioned that the holotype of T. racemosa is deposited at P. However, the material deposited in P ( P00665333 ) corresponds to the original drawing that was published in the protologue (tab. 61 from Bonpland et al. 1815 [1816]). Moreover, although P00665333 corresponds to original material (see Art. 9.4 ICN), it cannot be the holotype since it was not cited by the author as type (see Art. 9.1 ICN).

The protologue of Triaena racemosa provides a locality (apricis inter Guanaxuato et Villalpando), the only original material (other than the illustration from the protologue) that was traced is deposited in B. Therefore, the specimen BW01795010 is designated as lectotype, according to Art. 9.3 and 9.6 ICN, since this matches the protologue, has mature spikelets and corresponds to the current concept in Bouteloua (see e.g., Gould 1979, Herrera-Arrieta et al. 2004).

Notes on the type of Triathera gracilis :— The name T. gracilis appears published by Fournier in “Sertum Nicaraguense” ( Fournier 1880: 296), where he cites “Mexicanas plantas fasc. 2 p. 141”, a treatment that would take another six years to be published. In the protologue of T. gracilis, Fournier (1886) cites three collections: Berlandier 1016, Liebmann 578 and Liebman 582. However, the only one of these specimens that could be traced was Berlandier 1016, deposited in W. This material was also corroborated by L. Pignotti in 2010 (see label on W0026340). Here, W0026340 is designated as lectotype according to Art. 9.3 and 9.12 ICN, since it matches the protologue, shows reproductive structures, and corresponds to the current concept in Bouteloua (see e.g., Gould 1979, Herrera-Arrieta et al. 2004).

Note on the name Eutriana racemosa Trinius ex Fournier (in Fournier 1880: 296) nomen nudum:— Fournier (1880) cites Eutriana racemosa as a synonym of Triathera gracilis adding “msc. in herb. Petrop.”, a name never formally published by Trinius (who died in 1844) and lacking a proper description or diagnosis.

Notes on the type of Dinebra cristata :— Presl’s “Reliquiae Haenkeanae” is based on the material collected by Thaddaeus Haenke in America, Philippines and Mariana islands, as part of the scientific expedition led by Alessandro Malaspina from 1789 to 1794 ( Presl 1830, Ramos & Alonso 2018). In the protologue of D. cristata only a locality is provided “ hab. in Mex. ” ( Presl 1830). The material collected by Haenke is deposited in the herbaria PR and F (see HUH-Index of Botanists 2023). Some sources mention that the type material of D. cristata is deposited in PR ( TROPICOS 2023, Herrera-Arrieta 2004), and after contacting PR herbarium staff, it was corroborated that a specimen of D. cristata collected by Haenke in Mexico is currently in that collection (Fig. 4). This is probably the specimen from the picture on the US 00610858 sheet and the origins of the fragments that were corroborated by Peterson in 1998 (see label on sheet US 00610858). Here, PR203601 is designated as lectotype according to Art. 9.3 and 9.6 ICN, since it matches the protologue, shows reproductive structures, and corresponds to the current concept in Bouteloua (see e.g. Gould 1979, Herrera-Arrieta et al. 2004).

Taxonomic notes on Bouteloua juncea and Bouteloua triaena : —In 1812, Beauvois published the name Triathera juncea under the authority of Desvaux. In the protologue no collector or collection number are mentioned, but an illustration of the synflorescence and spikelet is included.

Desvaux (1813) amended the description of Triathera Desvaux (1810: 188) and accepted the specific epithet “ juncea ” and added “ Habitat in Hispaniola ” (see also Hitchcock & Gase 1917). Three years later, Kunth described the genus Triaena Kunth (in Bonpland et al. 1815 [1816]: 144) and the species Triaena racemosa based on a specimen collected in Guanajuato, Mexico. Kunth mentioned that Triaena is very similar to Triathera .

In 1825, Sprengel published the new name Atheropogon triaena for Triaena racemosa and mentioned that this species is distributed in Mexico. In that same publication, Sprengel proposed the new name A. domingensis for Triathera juncea and mentioned that it is distributed in Hispaniola.

In 1882, Bentham proposed the new name Bouteloua triathera Bentham (1882: 104) with which he erroneously refers to both: Triathera and Triaena . However, this is a superfluous and illegitimate name (Art. 52 ICN). Some years later, Scribner noted the mistake made by Bentham (1882) and proposed the new combination Bouteloua triaena for Atheropogon triaena and, as a synonym, he included Bouteloua triathera adding the legend “ in part ”.

At the beginning of the 20th century, Griffiths published Triaena juncea as a new combitaion for Triathera juncea based on the illustration from Beauvois (1812). However, Griffiths (1912) erroneously referred as Triaena juncea to specimens collected in Mexico. Those specimens and the illustration provided by Griffiths (1912) correspond to Bouteloua triaena , as described by Scribner (1891), and not to Triathera juncea . In the list of synonyms, Griffiths (1912) erroneously included Bouteloua triaena , Triaena racemosa , Triathera gracilis . A year later, Hitchcock, based on the work of Griffiths (1912), proposed Bouteloua juncea as a new combination to Triathera juncea , and erroneously referred with this name to specimens collected in Mexico and listed as synonyms Bouteloua triaena and Triaena racemosa .

Subsequently, Hitchcock and Chase (1917) reviewed material from the West Indies, which does not match the description provided by Griffiths (1912). They also mentioned that before the material collected in Hispaniola (Buch 1910 [not seen] and Britton 4918 MO-690997 [image!]) and consulted by them, the Mexican Bouteloua triaena (cited by them as B. triana ) was apparently the only species to which the illustration from Beauvois (1812) could apply. This was probably the reason why Bentham and Griffiths considered the species from the Hispaniola and the species from Mexico as the same one. This time, in the list of synonyms for B. juncea, Hitchcock and Chase (1917) did not include Bouteloua triaena and Triaena racemosa .

Although morphologically similar, B. triaena and B. juncea can be easily distinguished from each other ( Table 1 ).