Commelina rufipes Seubert (1855: 265–266)

Hassemer, Gustavo, 2017, Taxonomic and nomenclatural notes on neotropical Commelina (Commelinaceae), and an identification key for Brazil, Guyana, Paraguay, Suriname and Uruguay, Phytotaxa 303 (2), pp. 101-117 : 108

6. Commelina rufipes Seubert (1855: 265–266)

≡ Phaeosphaerion persicariifolium var. rufipes (Seub.) Clarke (1881: 137)

≡ Athyrocarpus rufipes (Seub.) Standley in Standley & Calderón (1925: 47)

≡ Phaeosphaerion rufipes (Seub.) Standley & Steyermark (1952: 22)

≡ Commelinopsis rufipes (Seub.) Hunt (1981: 195)

Lectotype (designated here): — BRAZIL. São Paulo: 1817, C. F. P. von Martius s.n. (M-0210921! [ Fig. 5 ]; isolectotype M-0210920!).

= Commelinopsis glabrata Hunt (1981: 195–197) , syn. nov.

≡ Commelina rufipes var. glabrata (D.R.Hunt) Faden & Hunt (1987: 122)

Holotype: — TRINIDAD AND TOBAGO. Trinidad , Irois Forest district under cacao trees in quantities, 25 January 1928, W. E. Broadway 6716 (K-000363259! [ Fig. 6 ]).

Distribution: —Neotropical, occurring from southern Mexico to Paraguay and central Brazil, including Trinidad and possibly some other Caribbean islands ( Hunt 1994).

Habitat: —Forest understorey.

Conservation status: —Least Concern (LC). This species has a wide distribution and is common through its range.

Notes: —The protologue of C. rufipes ( Seubert 1855: 265–266) provides the following information on the type: “ Crescit in Brasiliae prov. St. Pauli: M. [Martius] in Herb. Reg. Monac. ”. There are two sheets kept at M (M-0210921 and M-0210920) that can be considered original material for this name; the specimens on these two sheets evidently belong to the same species. These two sheets have labels with different numbers (76 and 77, respectively), which at first would suggest that they are not part of the same gathering; however, these labels are not Martius’ collector numbers, as they were added much later by A. Toepffer as part of an effort to organise the collections housed at M (Hans-Joachim Esser, pers. comm.). Only one of these sheets contains information on the collection date (1817, on M-0210921). Here, I accept that these two sheets can be considered as belonging to the same gathering, and therefore, duplicates. One of these two sheets (M-0210921; Fig. 5 ) is annotated with Seubert’s handwriting: “ Commelyna ochreata rufipes mihi ”; therefore, I here designate this sheet as the lectotype of C. rufipes .

One hundred and twenty-six years after the description of Commelina rufipes , Commelinopsis glabrata was described for Trinidad. Hunt (1981) noted this was a widespread species in tropical America which was hitherto erroneously identified as Commelinopsis persicariifolia ( Redouté 1816: tab. 472) Pichon (1946: 227). He presents the new species as similar to Commelinopsis rufipes (≡ Commelina rufipes ), but differing by the glabrous bracts, slightly larger leaves, and glabrous leaf sheets. In fact, he admits that “ C. rufipes and C. glabrata , when more fully studied, may prove to be conspecific”. Six years later, Faden & Hunt (1987) place this taxon into the genus Commelina at varietal rank: C. rufipes var. glabrata . Since then, this taxon has been accepted in every work that included C. rufipes (e.g., Barreto 1997, 2005, Aona & Leoni 2006, Espejo-Serna et al. 2009, Fernández & Cayola 2014, Aona 2015, Aona & do Amaral 2016). I must highlight here that Tropicos (http://tropicos.org) erroneously mentions that Fernández & Cayola (2014) accept C. rufipes var. glabrata as a synonym of C. rufipes . A careful reading of Fernández & Cayola (2014: 516–517) reveals that the authors confusingly list all infraspecific names under the species heading of C. rufipes , and later unambiguously cite C. rufipes var. glabrata as an accepted infraspecific taxon.

There appears to be no suitable character to distinguish between these two varieties, and hence I propose here the synonymisation of Commelinopsis glabrata under Commelina rufipes . With the revision of herbarium specimens from the entire range of C. rufipes I could observe that indumentum and leaf size vary greatly within this species, and this variation does not follow a geographic pattern. The indumentum of the leaf sheaths is today considered a distinguishing character between the two varieties ( Barreto 1997, Aona & Leoni 2006, Aona & do Amaral 2016). The leaf sheaths of C. rufipes vary from being completely glabrous to completely covered in a dense red indumentum but intermediates linking these two extremes are common. Furthermore, I should highlight that the leaf sheaths of the type specimen of Commelinopsis glabrata (K-000363259; Fig. 6 ) are not completely glabrous.

Figures

FIGURE 5. Lectotype of Commelina rufipes (C.F.P. von Martius s.n., M-0210921). Published with permission of Botanische Staatssammlung München.

FIGURE 6. Holotype of Commelinopsis glabrata (W.E. Broadway 6716, K-000363259). Published with permission of Royal Botanic Gardens, Kew.Available online at: http://specimens.kew.org/herbarium/K000363259.