Commelina rubens Redoute

Commelina rubens Redouté Commelina rubens Redouté (Redouté 1813: pl. 367). Etymology From the Latin ʻ rubēns ʼ (meaning ʻredʼ), in reference to its red to vinaceous stems and leaf-sheaths. Type material Original illustration of Les Liliacées at the W. Graham Arader Gallery and later published in Redouté 1813: pl. 367; lectotype, designated here. Remarks Commelina rubens has previously been compared with C. pallida. It has also been erroneously considered to have been validly published by Kunth (1843: 659) (e.g., Tropicos.org 2025) or as not validly published at all (i.e., Hassemer 2020). As stated by Hassemer (2020), Kunth merely cites C. rubens as similar to C. stricta Desf., and thus the author deemed “ C. rubens Hort. Berol. ex Kunth ” as not validly published (Turland et al. 2018: Art. 36.1). Nonetheless, after much research, we were able to find this name to have been validly published by Redouté (1813). The protologue and original illustration (Redouté 1813: pl. 367) describe a species superficially similar to C. diffusa due to its procumbent stems, leaf-opposite inflorescences, spathe base free, subequal blue petals, and yellow antherodes and anthers. However, the inflorescence is described as having a single cincinnus, as shown in the illustration (Redouté 1813: pl. 367), making it impossible to represent C. diffusa or any Neotropical members of this species group. Other distinguishing features are the spirally-alternate leaves, very short inflorescence peduncle and the shape of the spathe (i.e., lanceolate, falcate, base subcordate to obtuse), the concave subequal petals, added to the hispid stems, leaf-sheaths and abaxially hispid leaf-blades. These combined characters strongly suggest this species belongs to the C. tuberosa group and is closely related to the also poorly understood C. persicariifolia. Both species are clearly distinct from C. tuberosa s. str. and are here reestablished as accepted. Commelina rubens was also cultivated in the gardens of the Muséum dʼHistoire naturelle Paris (Redouté 1813). However, the author states not knowing where the plant was originally collected. Similar to C. persicariifolia, we believe this plant most likely originated from Ecuador, based on our studies of the C. tuberosa group specimens from the region. The original illustration is here designated as the lectotype for this name, and we refrain from designating any epitypes at this moment before we have been able to analyse the members of the C. tuberosa group more carefully. Misapplied Palaeotropical names