Croton serratus Müller Argoviensis (1866: 647)

Medeiros, Débora, Valle, Luci De Senna, Esser, Hans-Joachim & Alves, Ruy José Válka, 2016, Floristic and taxonomic treatment of Croton subsect. Medea (Euphorbiaceae) from Brazilian campos rupestres, Phytotaxa 263 (3), pp. 167-201 : 185-187

7. Croton serratus Müller Argoviensis (1866: 647) .— Timandra serrata Klotzsch (1841: 198) ; nom. nud.— Croton timandra Baillon (1864: 351) ; nom. nud.— Croton serratus var. genuinus Müller Argoviensis (1866: 647) ; nom. inval.— Oxydectes serrata (Müll.Arg.) Kuntze (1891: 613) . Lectotype (designated here):— BRAZIL. Minas Gerais: without locality, no date (fl, fr), F. Sellow s.n. (G-DC 00312540!, isolectotypes BR 876102!, K 000186123!, K 000186124!, P 00634720!). ( Fig. 13 , A–K)

Croton serratoideus Radcliffe-Smith & Govaerts (1997: 188) .— Timandra dichotoma Klotzsch (1841: 198) ; nom. nud.— Croton brachiatus Mart. ex Baill. (1858: 368) ; nom. nud..— Croton serratus var. dichotomus Müller Argoviensis (1866: 647) .— Croton dichotomus (Müll.Arg.) Müller Argoviensis (1873: 187) ; nom. illeg. [non Croton dichotomus Willdenow (1805: 537) ].— Oxydectes dichotoma (Müll. Arg.) Kuntze (1891: 613) . Lectotype (designated here):— BRAZIL. Minas Gerais: without locality, no date (fl), C.F.P. von Martius Herb. Fl. Bras. 959 (G-DC 00312542!, isolectotypes K 000186125!, L 0145425!, L 0412978!, M 0089102!, M 0086103!, MICH 1104792!, P 00634721!).

Subshrubs, 0.2−0.6m tall, branches united in clumps,some erect, the lower branches procumbent,dense,inconspicuously or irregularly dichotomous, reddish. Leaves imbricate and concentrated at the branch apices, subsessile with the petiole 1.8−2 mm long; leaf blade punctuated, ovate or oblong-ovate to elliptic, 0.7−1.5 × 0.3−0.5 cm, base obtuse to acute, symmetric, margin serrate, with a gland on each tooth, apex acute, trichomes stellate sparse on both surfaces, concentrated along the margins and the midrib, penninerved, shortly palminerved at the base; stipules inconspicuous, lanceolate, 0.5−2 mm long, laciniate-glandulose, glabrous or with stellate trichomes on the adaxial surface, persistent. Inflorescences glomeruliform, 1−2 cm long, without a naked sterile zone between the basal pistillate flowers and the apical staminate ones, 2−8 flowers covered by the leaves; bracts lanceolate, stipitate to laciniate-glandulose, trichomes stellate on the adaxial surface, 2.8−3 mm long on the staminate flowers, 3−5 mm on the pistillate ones. Staminate flowers 6−8 per inflorescence; pedicel 2−3 mm long; sepals 5, ovate-lanceolate to lanceolate, 1.4−3 × 1 mm, margin entire, trichomes stellate on the adaxial surface and the abaxial apex of the sepals; petals 5, obovate-spathulate, unguiculate, 4 × 2.2 mm, margin entire, ciliate; stamens 9−11, filaments 2 mm long, glabrous or vilous at the base, anthers ovoid, 0.9−1 × 0.5 mm, glabrous. Pistillate flowers 1−2 per inflorescence, sessile or subsessile; pedicel 2 mm long; sepals 5, narrow-lanceolate, 4−6 × 1−1.3 mm, stipitate-glandulose, trichomes stellate on the adaxial surface, absent on the abaxial one; petals absent; ovary ovoid to globose, 1.5 × 1−1.5 mm, whitish, trichomes stellate; styles multifid, 2−3(−4) times branched at the base, 1.5−2 mm long, sparse trichomes stellate or glabrous. Capsules globose, 4 × 4 mm, trichomes stellate brownish; seeds ellipsoid, 3 × 2.6 mm.

Distribution: — Minas Gerais, Quadrilátero Ferrífero, Metropolitan Region of Belo Horizonte, 1390−1746 m elevation ( Fig. 14 ).

Additional specimens examined: — BRAZIL. Minas Gerais: Belo Horizonte, Serra do Curral , estrada BR−03, km 33, 25 July 1956 (fl), L. Roth s.n. (CESJ 15222, R) ; Betim, Serra do Rola Moça , March 1940 (fl), M. Barreto 10690 (BHCB, CESJ) ; Caeté, Serra da Piedade , 24 September 1936 (fl, fr), M. Barreto 8172 (BHCB) ; Itabira, Pico Itabira do Campo , no date (fl), L. Riedel 110 (P) ; 20 December 1888 (fl, fr), C.A.W. Schwacke s.n. (R 100768); March 1893 (fl), F. Mager s.n. (OUPR 6123); 1904 (fl), C.A.W. Schwacke s.n. (BHCB 587); Serra de Itabira do Campo , no date (fl), L. Damazio s.n. (RB 78092) ; Moeda , 1844 (fl), P. Claussen s.n. (P) ; Serra da Moeda, M.B.R. área, 24 February 1986 (fl), A. Kassis et al. s.n. (OUPR 5322); Serra da Moeda, Morro da Piedade , 26 October 1988 (fl), S.B. Velten et al. 01 (BHCB) ; 24 April 1990 (fl), J.A. Paula & S.B. Velten s.n. (BHCB 17792).

Taxonomic notes: —This species differs from the other taxa of subsect. Medea by its habit with densely subdivided branches, part of them procumbent. The dichotomous branching pattern is not evident at first sight.

Klotzsch (1841) described the genus Timandra Klotzsch , to which he assigned three nomina nuda: T. serrata Klotzsch (1841: 198) , T. erythroxyloides Klotzsch (1841: 198) , and T. dichotoma Klotzsch (1841: 198) . None of these names were validly published under Timandra , but Müller Argoviensis later described T. serrata as Croton serratus Müller Argoviensis (1866: 647) and placed T. dichotoma under Croton serratus var. dichotomus Müller Argoviensis (1866: 647) (also see Wheeler 1975, who lectotypified the genus Timandra with Croton serratus ). These taxa were described by Müller Argoviensis again in 1873, but C. serratus var. dichotomus was then treated at species level as Croton dichotomus Müller Argoviensis (1873: 187) . Radcliffe & Govaerts (1997) provided the replacement name Croton serratoideus (1997) for Croton dichotomus Müller Argoviensis , because the name was illegitimate due to the priority of Croton dichotomus Willdenow (1805: 537) .

Figures

FIGURE 13. Croton serratus. A. Habit, uprooted plant; B. Stipule; C. Inflorescence; D. Staminate flower: E. Stamen, F. Sepal (ventral side), G. Petal (ventral side); H. Pistillate flower; I. Gynoecium; J. Fruit; K. Seed (ventral side) (after L. Roth s.n. 15222 (CESJ)).

FIGURE 14. Distribution map of Croton serratus.