Commelina tuberosa Linnaeus (1753: 41)

Hassemer, Gustavo, 2017, A clandestine in the flora of Brazil: Commelina clandestina (Commelinaceae), Phytotaxa 323 (3), pp. 289-294 : 290

Commelina tuberosa Linnaeus (1753: 41)

Type: — MEXICO. S.d., Anonymous s.n. (lectotype [designated by Hunt 1994: 173] LINN- 65.8!). Image of the lectotype available online at: http://linnean-online.org/854.

= Commelina clandestina Martius (1839: 2 , 4), syn. nov.

Type: — GERMANY. BAYERN: München: [cultivated], 1832, Anonymous s.n. (lectotype [designated here] M-0243579! [ Fig. 1 ]).

= Commelina clandestina Hort.Berol. ex Kunth (1843: 46) , nom. illeg., syn. nov.

≡ Commelina graminifolia var. clandestina (Hort.Berol. ex Kunth) C.B. Clarke (1881: 152)

Type: — GERMANY. Berlin: [cultivated], August 1832, Anonymous [Hort. Berol.] s.n. (lectotype [designated here] B-100715995! [ Fig. 2 ]).

Notes: —It is clear that C. clandestina Mart. was described from plants cultivated at the Munich Botanical Garden ( Martius 1839). I was able to locate two specimens that can be considered original material for this name, both kept at M: M-0243579 and M-0243580. These specimens are dated 1832, and must have been seen by Carl Friedrich Philipp von Martius, who was at Munich at the time. The specimens on both sheets are morphologically very similar, and most probably were grown from the same batch of seeds. I designate here one of these specimens, M-0243579 ( Fig. 1 ), which is the most complete and best preserved among the two, as lectotype of C. clandestina Mart. , in accordance with Arts. 9.2, 9.3, 9.11 and 9.12 of the Code. This specimen has a label written “28”, but this is not a collector number, as it was added by Adolph Toepffer as an effort to organise the collections kept at M (Hans-Joachim Esser, pers. comm.).

Nevertheless, the name C. clandestina Hort.Berol. ex Kunth , considering that it was separately and validly published, is to be referred to another type. It is clear that this name was based on plants cultivated in Berlin ( Kunth 1843). I was able to locate two specimens that can be considered original material for this name, both kept at B: B-100715995 and B-100715996. I designate here one of these specimens, B-100715995 ( Fig. 2 ), which has a clear reference to Kunth (“ Ex herb. Kunth ”), as lectotype of C. clandestina Hort.Berol. ex Kunth , in accordance with Arts. 9.2, 9.3, 9.11 and 9.12 of the Code.

A careful study of the type specimens makes it clear that both C. clandestina names should be considered synonyms of C. tuberosa Linnaeus (1753: 41) , a species that occurs from Mexico to north-western Argentina ( Fernández & Cayola 2014, Hunt 1994, Zuloaga et al. 2008), and therefore I propose here these synonymisations. The type specimens of both C. clandestina names have morphological features characteristic of C. tuberosa , including the invaginating leaf blades and the pedunculate spathes with margins free to the base, pilose externally, wider at the medial part than nearer the base. These identifications are in accordance with the identification key in Hunt (1994). Furthermore, the original specimens for both C. clandestina names were compared with herbarium specimens (see list of herbaria consulted in Material and methods).

In South America, C. tuberosa is restricted to the Andean region, and has never been recorded in Brazil, apart from the doubtful citation of C. clandestina Mart. in Steudel (1840), repeated in Jackson (1895), which is most probably erroneous. Due to the extensive natural range of C. tuberosa , it is not possible to ascertain the origin of the seeds from which the type specimens of both C. clandestina names were grown in Munich and Berlin. However, considering the current taxonomic and biogeographic knowledge of Commelina , it appears as extremely improbable that these seeds originated from Brazil, and therefore I argue for the removal of the record of C. clandestina from the Flora of Brazil.

Figures

FIGURE 1. Lectotype of Commelina clandestina Mart. (Anonymous s.n., M-0243579). Published with permission of Botanische Staatssammlung München.

FIGURE 2. Lectotype of Commelina clandestina Hort.Berol. ex Kunth (Anonymous s.n., B-100715995). Published with permission of Botanischer Garten und Botanisches Museum Berlin-Dahlem. Available online at: http://herbarium.bgbm.org/object/B100715995.