Croton suassunae Y. Rossine & A. L. Melo (2020: 249)

Rossine, Yuri, Melo, André Laurênio De, Athiê-Souza, Sarah Maria & Sales, Margareth Ferreira De, 2023, Understanding the “ Marmeleiros ”: a taxonomic treatment of Croton sect. Lasiogyne (Euphorbiaceae) in Brazil, Phytotaxa 584 (4), pp. 219-250 : 241

10. Croton suassunae Y. Rossine & A. L. Melo (2020: 249) .

Holotype:— BRAZIL. Bahia: Rio de Contas, road to fazenda Marion , from Rio de Contas , 13°37’38”S, 41°45’25”W, 912 m, 3 February 2004 (staminate), R. M. Harley et al. 54794 (UFP [ UFP69262 !]; isotypes: HUEFS [ HUEFS80175 !], K [ K001184124 !], ASE [ ASE21976 !], JPB [ JPB56409 !]) . Fig. 8 (a–f), 9 (b)

Description: —Dioecious shrub, 1.5–3 m tall; latex translucent to yellowish; branching sympodial, branches cylindrical, sometimes slightly striated, brown to ferruginous, with lepidote trichomes. Leaves alternate; stipules lanceolate, ca. 0.7 × 0.2 cm, usually deciduous, with lepidote trichomes; petiole cylindrical, 0.3–0.7 cm long, with lepidote trichomes; leaf blade chartaceous, ovate to elliptic, 2–4 × 1.5–2.5 cm, strongly bifacial, adaxial face green to dark green with stellate to stellate-lepidote trichomes, or glabrous, abaxial face shiny, silver to ferruginous, with lepidote trichomes, base rounded to cordate, margins entire, apex acute to narrowly acute, venation eucamptodromous, with 5–11 secondary veins; Thyrses 4–13 cm long (staminate) and 2–10 cm long (pistillate), axillary, with lepidote to stellate-lepidote trichomes, peduncles 0.6–1 cm long; cymules unisexual, lax, up to 3 staminate flowers, pistillate flowers solitary; bracts deciduous, lanceolate, 0.4–0.7 × 0.2–0.3 mm, margins entire, apex acute, with stellate-lepidote trichomes. Staminate flower with pedicels 1.7–2 mm long; sepals silver to ferruginous, united for ⅔ of their length, ovate, ca. 1.3 × 1 mm, margins entire, apex acute, with lepidote trichomes externally, stellate-lepidote internally; yellow to golden petals, oblong, ca. 1.5 × 0.6 mm, margins entire, apex rounded, with stellate trichomes; stamens 10–15, filament 1.5–2 mm long, anther elliptic, ca. 0.5 × 0.3 mm; nectary disk 5-lobed, apex of lobes acute, with stellate-lepidote trichomes. Pistillate flower with pedicels ca. 2 mm long; sepals silver to ferruginous, free, spatulate, equal in size, 2–2.5 × 0.5 mm, reduplicated vertically, margins entire, apex rounded to acute, with lepidote trichomes externally, stellate-lepidote internally; petals yellow, narrowly triangular, ca. 0.8 × 0.3 mm, margins entire, apex narrowly acute, with stellatelepidote trichomes; ovary spheroid, ca. 2 × 2.3 mm, with lepidote trichomes, styles ascending, united at the base, 2-fid, 6 stigmatic tips, with stellate-lepidote trichomes; nectary disk 5-lobed, apex of lobes rounded, with stellate-lepidote trichomes to glabrescent. Capsule silver to ferruginous, spheroid, 4–4.5 mm diam., unlobed, surface non-muricate, with lepidote trichomes; columella 2.8–3 mm long, striated, apex flattened. Seed brown, ellipsoid to long ellipsoid, 3.2 × 2.2–2.5 mm, smooth, caruncle elliptic.

Vernacular name: — Marmeleiro de touceira.

Distribution and habitat, conservation status and phenology: — Croton suassunae is native to the Caatinga domain, also occurring in transition areas between Caatinga and Cerrado, and Caatinga and Atlantic Forest ( Rossine et al. 2020a). It is found in Bahia, Ceará, Minas Gerais (new record), Pernambuco and Piauí, in clayey and limestone soils, or on rocky outcrops ( Fig. 9 , b). This species was evaluated as of least concern (LC) by Rossine et al. (2020a); we keep that classification here. Although its small AOO (ca. 160 km 2), it has populations in environmental protection areas and areas of difficult access in terms of anthropization, such as cliffs and mountainous areas, and an EOO of 536,575.348 km 2. Flowering and fruiting from December to June.

Notes: — Croton suassunae stands out for being the only dioecious species in section Lasiogyne . It was a segregated from C. tricolor ( Rossine et al. 2020a) , and also resembles C. claussenianus , although it can be easily differentiated by having unisexual inflorescences and 2-fid styles (vs. bisexual and 2-partite); other characters are presented in the comments concerning C. claussenianus .

Representative specimens: — BRAZIL. Bahia: Morro do Chapéu, Comunidade Cristal, Buraco da Duda ou Burac „o, 11º82’86” S, 41º30’47” W, 19 May 2004, E . Melo 5612 (HUEFS). Ceará: Crato, Flona do Araripe , 28 April 1999, L. W . Lima-Verde 1343 (EAC). Minas Gerais: Medina , rod. BR-116, 10 km S de Medina, 20 November 1985, G . Hatschbach 50014 (MBM). Pernambuco: Ipubí, a 3 km de Serra Branca, 7º83’33” S, 40º46’66” W, 15 February 1984, G . Fotius 3764 (HUEFS). Piauí: Caracol, entrada do Parque , estrada à direita da guarita, área antropizada, 9º21’30” S, 43º46’61” W, 26 February 2011, E . Melo 9226 (HUEFS).

Figures

FIGURE 8. a–f Croton suassunae: a flowering branch (staminate), b flowering branch (pistillate), both a and b showing sympodial ramification, c lanceolate stipules, d staminate flower of ca. 15 stamens, e pistillate flower with sepals slightly reduplicated vertically, spheroid ovary, and ascendant and 2-fid styles, f spheroid fruit, showing sepals internally glabrous.g–k C. tricolor: g flowering branch with monopodial ramification h lanceolate stipules, i staminate flower of ca. 12 stamens, j pistillate flower with sepals strongly reduplicated vertically, glabrous internally, ovoid ovary and, patent and multipartite styles k long ellipsoid to ovoid fruit.

FIGURE 9. Distribution of some species of section Lasiogyne. a Croton limae, C. micans and C. sacaquinha; b C. suassunae and C. tricolor.