Euphorbia chrysophylla (Klotzsch & Garcke) Klotzsch ex Boissier (1862: 104)

Silva, Otávio Luis Marques Da, Cordeiro, Inês & Caruzo, Maria Beatriz Rossi, 2014, Synopsis of Euphorbia (Euphorbiaceae) in the state of São Paulo, Brazil, Phytotaxa 181 (4), pp. 193-215 : 196-198

3. Euphorbia chrysophylla (Klotzsch & Garcke) Klotzsch ex Boissier (1862: 104) ( Fig. 1G–I ).

Tithymalus chrysophyllus Klotzsch & Garcke in Klotzsch (1860: 72).— Euphorbia collina var. chrysophylla (Klotzsch & Garcke) Subils (1977: 215) .— Lectotype (designated here):— BRAZIL. Minas Gerais: Serra da Moeda, F. Sellow s.n. (holotype B†, photo F!, lectotype BR 05102211!, isolectotypes LD1444693!, P00607247!, K00253932!, K00253934!).

Distribution and habitat:— Euphorbia chrysophylla occurs in Brazil, Bolivia and Northeastern Argentina. In São Paulo, the species is known by a single collection (from Itirapina Ecological Station), where it occurs in swampy areas in cerrado vegetation.

Representative Specimen:— BRAZIL. São Paulo: Itirapina , 20 April 2009, J.S. Tannus 750 (SPSF) .

Taxonomic notes:— Euphorbia chrysophylla is similar to E. elodes , but can be distinguished from it by leaf shape (elliptic to narrowly elliptic in E. chrysophylla vs. obovate in E. elodes ), number of lateral axes of the pleiochasia (5 in E. chrysophylla vs. 3 in E. elodes ) and cyathial glands (5 in E. chrysophylla vs. 4 in E. elodes ). On dried specimens, leaves of E. chrysophylla are distinctly involute, a character not observed in E. elodes . Another similar species is E. rhabdodes , which also has pleiochasia with 5 lateral axes, but E. chrysophylla differs from it by leaf venation (actinodromous in E. chrysophylla vs. cladodromous in E. rhabdodes ) and margin (involute in E. chrysophylla vs. revolute in E. rhabdodes ), number of cyathial glands (5 in E. chrysophylla vs. 4 in E. rhabdodes ) and seed coat (verrucose in E. chrysophylla vs. rugose in E. rhabdodes ).

Euphorbia chrysophylla was recognized by Riina & Berry (2013) as a synonym of E. portulacoides Linnaeus (1753: 456) subsp. c ollina ( Philippi 1857: 41) Croizat (1943: 188). However, the synonymization of E. collina with E. portulacoides made by Croizat was not accepted by Subils (1977). One of the characteristics distinguishing Euphorbia collina Philippi (1857: 41) from E. portulacoides is the color of cyathial glands, which is green in E. collina and purple in E. portulacoides , a characteristic also observed by Boissier in the treatment of tribe Euphorbieae for Candolle’s Prodromus ( Boissier 1862) . Apparently, Croizat (1943) was unable to see this difference, since his synonymization was based only on involucre and fruit sizes. Subils (1977) recognized, therefore, two distinct species: E. collina , with 7 varieties, one of them E. collina var. chrysophylla , and E. portulacoides , with 3 varieties.

We believe the synonymization of Euphorbia chrysophylla under E. collina is not supported due to the following characteristics which are different between both species: leaf shape (elliptic to narrowly elliptic in E. chrysophylla and linear in E. collina ), number of lateral axes of the pleiochasia (5 in E. chrysophylla and 3 in E. collina ) and seed coat (verrucose in E. chrysophylla and smooth in E. collina ), and so we accept the name E. chrysophylla .

Figures

FIGURE 1. A–D: Euphorbia adenoptera. A. habit, B. branch with cyathia, C. abaxial surface of a branch, D. cyathium. E–F. Euphorbia bahiensis. E. synflorescence, F. branch with cyathia. G–I: Euphorbia chrysophylla. G: habit, H: leaves, I: branch with cyathia. Photos: A–D: O.L.M. Silva, E–F: M. Pastore, G–I: R. Dayrell.