Croton macrocalyx Martius ex Baillon 1864
Creators: name: Rossine, Yuri
name: Melo, André Laurênio De
name: Athiê-Souza, Sarah Maria
name: Sales, Margareth Ferreira De
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Euphorbiaceae
Croton
Croton macrocalyx

description: Croton macrocalyx Martius ex Baillon (1864: 303).
— Croton janeirensis Radcliffe-Smith & Govaerts (1997:187), nom. illeg. superfl.
Lectotype (designated here):— BRAZIL. Bahia: Ilhéus “ad fl. Ilheos”, 1817–1820, C.F.P. von Martius s.n. (P [P00623527!, fragment at F [F0056159F!]; isolectotype: K [K000186157!]). Remaining syntypes:— BRAZIL. Rio de Janeiro: “Sables presque purs, entre le Sitio do Paulista et celui do Pires”, 1816–1821, A.F.C.P. de Saint-Hilaire, cat. B 2, n. 208 (P [P00623529!, P00623528!]).
Notes: — Croton macrocalyx was originally named by Martius in schedula (on an herbarium label only), and then later described by Baillon (1864). This name was accepted by Müller (1873) and Oliveira et al. (1989). Radcliffe-Smith & Govaerts (1997) proposed C. janeirensis to replace the name C. macrocalyx Mart. ex Baill., considering it to be an illegitimate name and a later homonym of C. macrocalyx Ehrenberg (in Schweinfurth 1862). We realized, however, that C. macrocalyx Ehrenberg is a nomen nudum, never properly described or illustrated, and it was cited only in synonymy (pro syn.) of Chrozophora brocchianna by Schweinfurth (1862: 9) and not mentioned in any other treatment. Thus, C. macrocalyx Mart. ex Baillon is the correct name for this species, and not C. janeirensis. Van Ee et al. (2011) included C. janeirensis in their list of sect. Lasiogyne, whereas the name C. macrocalyx was not included as a valid name.
Baillon (1864) published Croton macrocalyx based on two collections, Martius s.n., deposited in the herbarium “ Lamb.” and Saint-Hilaire cat. B 2 n. 208, without any indication of the herbarium, requiring the choice of a lectotype, as they are syntypes. The “ Lamb.” Herbarium belonged to Aylmer Bourke Lambert, a British botanist whose collections were sold after his death, mainly to BM, but also to K, and G herbaria. (Stafleu & Cowan 1979). A Martius collection from Herbarium Less. (Delessert, currently in G) was excluded in the protologue by Baillon (“ nunc Less. ”). The Saint-Hilaire collections are mostly found at P. One specimen of Martius s.n. was found in K (K186157) and another one in P (P623527), in addition to a fragment in F (F0056159F), and two specimens of Saint-Hilaire cat. B 2 n. 208 were found in P (P623528, P623529). The specimen P623527 (Martius s.n.) is chosen as lectotype due to its good state of conservation and because it is deposited in the herbarium where most of the types described by Baillon are located (Stafleu & Cowan 1976). Besides that, it has open staminate and pistillate flowers, well representing the description in the protologue.
Croton macrocalyx is the only species attributed to section Lasiogyne that has leaf blades with crenate to dentate margins. Its general aspect resembles members of section Barhamia (Klotzsch 1853: 104) Baillon (1858: 367). Van Ee et al. (2011) could not sample this taxon in their phylogenetic analysis, so its sectional placement was based solely on morphological features. This species clearly needs a more detailed examination and molecular phylogenetic analysis to confirm its placement in section Lasiogyne.
description: Published as part of Rossine, Yuri, Melo, André Laurênio De, Athiê-Souza, Sarah Maria & Sales, Margareth Ferreira De, 2021, Taxonomic updates in Brazilian species of Croton sect. Lasiogyne (Euphorbiaceae): new synonyms and lectotypifications, pp. 82-90 in Phytotaxa 490 (1) on pages 87-88, DOI: 10.11646/phytotaxa.490.1.7, http://zenodo.org/record/5756700