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.