Croton compressus Lamarck (1786: 208)

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, Phytotaxa 490 (1), pp. 82-90 : 84-87

Croton compressus Lamarck (1786: 208) .

— Oxydectes compressa (Lam.) Kuntze (1891: 611) .

Lectotype (designated by van Ee 2011: 30):— BRAZIL. Rio de Janeiro: without further locality, 1767, P. Commerson s.n. ( P [ P-LA382064 !, upper plant only] ; isolectotypes: F [ F970409 !], FI [ FI011652 !], MPU [ MPU14777 !], P [ P00493370 !, P00493371 !, P00674046 !, P-JU16345 ]) .

Croton gonocladus Spring ex Martius (1837: 119) .— Lasiogyne brasiliensis Klotzsch (1843: 418) .— Croton brasiliensis Martius ex Klotzsch (1843: 419) , nom. nud. Lectotype (designated here):— BRAZIL. Rio de Janeiro: without further locality, without date, C.F.P. von Martius Herb. Fl. Bras. 163 (M [M0086105!]; isolectotypes: BR [BR0000008553041!], FI [FI011651!], G-DC [G00311375!], GH [GH00047304!], HAL [HAL0136203!], M [M0086106!, M0089100!, M0089101!], P [P00623111!, P00623112!, P00623113!], SP [SP000658!], TUB [TUB009128!, TUB009129!]). Remaining syntypes: BRAZIL. Without further locality, 1836, M. Ackermann 13 (BR [BR0000008550477!]). BRAZIL. Without further locality, without date, J.B.E. Pohl s.n. (BR [BR0000008553379!]).

Croton subcompressus Müller Argoviensis (1866: 557) , syn. nov. — Oxydectes subcompressa (Müll.Arg.) Kuntze (1891: 613) . Type :— “Patria ignota, verisimiliter America meridionalis aut Mexico ”, without date, Anonymous s.n. (Holotype: G-DC [G00311369!]).

Notes: — Croton gonocladus was published by Martius (1837) from a name proposed by Spring in schedula and based on material from Rio de Janeiro, without indication of collector or number. Three collections ( Ackermann 13, Martius s.n. and Pohl s.n.), deposited in BR, G and M, where part of Martius’ original collections, are consistent with the protologue and were probably used by the author in the description of C. gonocladus . Van Ee (2011) cited Martius 163 as the type collection of the species, but did not indicate a holotype, citing all the analyzed specimens as isotypes. Moreover, as Martius (1837) did not indicate a collector and collection number, and the above-mentioned collections exist in G, BR and M, the three should be recognized as syntypes of C. gonocladus , requiring lectotypification. The mentioned Martius 163 (van Ee 2011) is in fact Martius, Herb. Fl. Bras. 163, a distribution number of a series used by the author, instead of the collection number. We agree with van Ee (2011) that the collection for the lectotypification of C. gonocladus should be Martius, Herb. Fl. Bras. 163 (cited in van Ee [2011] as Martius 163), as it is from a collection by Martius himself, and has a greater number of duplicates. We selected the sheet M0086105 as lectotype, since this is the best-preserved material, and shows that L. brasiliensis and C. gonocladus are in fact homotypic, due to Klotzsch’ handwritten annotation “ Lasiogyne brasiliensis ” on that sheet’s label.

Van Ee (2011) selected Martius s.n. as lectotype of Lasiogyne brasiliensis , and recognized this name as heterotypic with C. gonocladus . As we understand here, the type collection of L. brasiliensis is M0086105, therefore these names are homotypic. Still, the older name, C. gonocladus , needs lectotypification.

When establishing Croton subcompressus, Müller Argoviensis (1866) characterized the species mainly by the stellate indumentum, eglandular leaf with pinnate venation, and by the recurved, ovate-triangular sepals of the pistillate flower. He compared C. subcompressus with C. compressus , differentiating them by the size of some structures (e.g. leaf blade, stipules and staminate flower), considered smaller in C. subcompressus . However, after analyzing the protologue and the type collection of C. subcompressus ( Fig. 1 ), we concluded that the characters used by Müller Argoviensis (1866) to distinguish these species, are in fact, expressions of the phenotypic plasticity of a single species. Thus, C. subcompressus is proposed here as a synonym of C. compressus . If indeed the type of C. subcompressus belongs to C. compressus , then we can reasonably conclude that it came from Brazil, not Mexico, and most likely from Espírito Santo, Rio de Janeiro or São Paulo states, where C. compressus is known to occur.

Figures

FIGURE 1. Holotype of Croton subcompressus at the Conservatoire et Jardin botaniques de la Ville de Genève (Switzerland), specimen G00311369.