Commelina platyphylla Klotzsch ex Seubert (1855: 262)

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 : 105

4. Commelina platyphylla Klotzsch ex Seubert (1855: 262)

Lectotype (designated here): — GUYANA. R. H. Schomburgk 1531 (B-100247303! [ Fig. 3 ]; isolectotype K-000363253!).

– Commelina platyphylla Klotzsch ex Schomburgk (1849: 897) , nom. inval. (Art. 38.1; see also Art. 38.3)

= Commelina platyphylla var. balansae Clarke (1881: 177)

≡ Commelina balansae (C.B.Clarke) Herter (1940: 148)

Lectotype (designated here): — PARAGUAY. L’assomption, dans les champs en friche, April 1875, B. Balansa 593 (K-000363250! [ Fig. 4 ]; isolectotypes G-00038182!, G-00489279!, P-01639104!, P-01742735!).

Distribution: —Eastern tropical and subtropical South America: northeastern Argentina, eastern Bolivia, Brazil, Guyana (where the type originated from), Paraguay, and Uruguay, in altitudes ranging from sea level to 1000 m ( Barreto 1997, Zuloaga et al. 2008, Fernández & Cayola 2014).

Habitat: —Open areas, such as cerrado grasslands.

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

Notes: — Commelina platyphylla was first published by Schomburgk (1849: 897) for Guyana; however, the name was not validly published since it lacked a diagnosis and description (Art. 38.1; see also Art. 38.3). This name was later validly published by Seubert (1855: 262), who indicated the material was collected by “[ R. H.] Schomburgk in Guyana anglica”, and cited it could also occur in northern Brazil. No further information was given on the type specimen. Since Johann Friedrich Klotzsch was in Berlin when both Schomburgk’s and Seubert’s names were published it is likely his specimens were there too. Therefore I designate here the specimen on a sheet kept at B (B-100247303; Fig. 3 ) as lectotype for C. platyphylla ; a duplicate (isolectotype) is kept at K (K-000363253) .

The authorship of C. platyphylla has been erroneously presented in recent literature such as Fernández & Cayola (2014) and Hassemer et al. (2016b), and the databases IPNI (http://www.ipni.org) and Tropicos (http://tropicos.org).

The name C. platyphylla var. balansae was published by Clarke (1881: 177), originally spelled “ Balansai ”, based on plants collected in Paraguay, Bolivia and Uruguay. He described this variety as differing from C. platyphylla by “foliis obtusis; seminibus oblongis”. Later, Herter (1940) raised this entity to species rank, without any explanation regarding this change. The protologue ( Clarke 1881: 177) provided the following information concerning the type: “ Paraguay (Balansa n. 593, floribus albis); Asuncion (Gilbert). Bolivia; in Andibus prope Chiquitos (D’Orbigny n. 942). Uruguay (Aug. de St-Hilaire n. 2566 partim, et n. 2567 partim; Lorentz n. 603 partim)”; all these gatherings are to be regarded as syntypes (Art. 9.5). As the first element mentioned, and being clearly in accordance with the description in the protologue, I chose a lectotype from the Balansa 593 specimens. Considering that Charles Baron Clarke worked for many years in Kew, I designate here a sheet kept at K (K-000363250; Fig. 4 ) as lectotype for C. platyphylla var. balansae .

Commelina platyphylla var. balansae has already been regarded as a synonym of C. platyphylla in taxonomic literature ( Bacigalupo 1964) and check lists ( Zuloaga et al. 2008, Fernández & Cayola 2014); however, some authors have accepted it as a separate taxon (e.g., Barreto 1997). Having had the opportunity to compare the types, I found no characters that permit to separate these two and therefore I agree with its synonymisation under C. platyphylla .

Figures

FIGURE 3. Lectotype of Commelina platyphylla (R.H. Schomburgk 1531, B-100247303). Published with permission of Botanischer Garten und Botanisches Museum Berlin-Dahlem.Available online at: http://herbarium.bgbm.org/object/B100247303.

FIGURE 4. Lectotype of Commelina platyphylla var. balansae (B. Balansa 593, K-000363250). Published with permission of Royal Botanic Gardens, Kew.Available online at: http://specimens.kew.org/herbarium/K000363250.