Sida brachyclada G.Guerra, 2025

Guerra, Gabriel C., Colli-Silva, Matheus, Bovini, Massimo G. & Harley, Ana Maria Giulietti-, 2025, Sida brachyclada (Malveae, Malvoideae, Malvaceae): a new threatened species from the semiarid mountains of Bahia, Brazil, Phytotaxa 715 (1), pp. 61-71 : 62-63

Sida brachyclada G.Guerra , sp. nov. ( Fig. 1 , 2 and 3C )

Type: — BRAZIL. Bahia: Sento Sé , Minas do Mimoso , Campo Largo , 1.169 m, 10º21′58”S 41º21′44.1”W, 07 October 2024, bd, fl. & fr., G. Guerra & R. L. Borges 515 ( holotype: ALCB 153528 !, isotypes: CBC!, HUEFS!)

Diagnosis: —This species is similar to Sida dubia Saint-Hilaire & Naudin (1842: 50) but can be distinguished by its shrubby habit with short lateral brachyblasts (vs. subshrub with absent brachyblasts), smaller leaves (4–)5–10(–15) mm long (vs. 10–35 mm), lax terminal flowers (vs. congested), and petals golden yellow with a distinct dark red basal spot (vs. pink to pale yellow without a conspicuous basal spot). Sida brachyclada and Sida maculata Cavanilles (1785: 20) share a shrubby and deciduous habit, ovate to elliptical leaves, and golden yellow flowers with a red spot. However, S. brachyclada differs by its shorter stipules, 1.2–4.5 mm long (vs. 5–10 mm), smaller leaves ( 10–60 mm long in S. maculata ), pubescent indumentum (vs. tomentose to villous) and 3-veined leaves (vs. 5–7-veined).

Description: —Shrub, erect, 30–50 cm tall. Stems cylindrical, reddish-brown to greenish with persistent brachyblasts bearing scars of deciduous leaves and stipules, pubescent to tomentose on younger portions and glabrescent on older ones, bearing stellate-multiradiate (rays ≤ 0.4 mm), glandular and sparse simple trichomes 0.8– 1.5 mm long. Stipules 1.2–4.5 mm long, narrowly triangular to subulate, green to vinaceous, deciduous. Petioles cylindrical, slightly sulcate at the base, 1.5–10 mm long, with stellate, glandular, and less frequently simple trichomes; blades discolorous, 3-veined, (4–)5–10(–15) × (2–)3–6(–8) mm, ovate, elliptical or rarely oblong, often conduplicate, base subcordate to cordate, apex obtuse, margins serrate to dentate, adaxial surface puberulent to pubescent, abaxial pubescent to tomentose, stellate-multiradiate, bifurcate and glandular trichomes on both sides (rare simple trichomes on the upper surface). Inflorescence axillary, consisting of solitary flowers concentrated distally on dolichoblasts, usually in an indeterminate lax corymbiform arrangement, rarely solitary on brachyblasts; flowers bisexual, 5-merous, dichlamydeous and heterochlamydeous; pedicels (8–)9–40(–48) mm long, articulated above the midpoint, often with vinaceous stripes, pubescent with stellate, glandular, and simple trichomes; calyx 6.0– 7.9 mm long, lobes 3–4.4 mm long, apices attenuate, less frequently acute, margins and midvein dark green to vinaceous, abaxial surface pubescent to tomentose with stellate, glandular and simple, or bifurcate, trichomes along the midvein, adaxial surface glabrescent, with few small hyaline trichomes; corolla golden yellow to orangish with dark red basal spot, petals 10–13 mm long, with glandular trichomes on the upper margin and hyaline trichomes on the base; staminal tube 3–3.3 mm long, glabrous or with few simple hyaline trichomes, filaments with glandular trichomes, anthers 0.7 × 1.2 mm; ovary 10- carpellate, 10-locular, 1.5–2 × 1.5–2 mm, broadly ovoid, pubescent on the upper half, styles 8–11, 6 mm long, connate up to the half their length, stigmas capitate. Fruit schizocarp, 4–4.7(–5.5) × 5.5–6 mm; mericarps 7–10, 3–3.2(–4) × 1.5–2 mm, reticulate at the dorsal side, laterally ribbed to reticulate, pilose on the upper half with simple and stellate hairs, punctate glandular trichomes uniformly distributed throughout the body, awns 1–1.5 mm, with retrorse and patent trichomes. Seeds 1 per mericarp, 2 mm long, with few glandular, simple, and bifurcate trichomes concentrated around the hilum and the superior ventral face.

Distribution and habitat: — Sida brachyclada is endemic to the state of Bahia , occurring in the Chapada Diamantina highlands and Serra da Jibóia ( Fig. 4 ), in ecotonal zones between cerrado and caatinga, on latosols or sandy soils ( Fig. 3A–B ).

Phenology: —Specimens with flowers were recorded in February, March, April, May, August, October and November. Only those collected in March, April, August and October bore mature fruits.

Conservation: —With an Extent of Occurrence (EOO) of 71,813 km ² and a highly restricted Area of Occupancy (AOO) of only 28 km ², this species shows a fragmented distribution across six isolated subpopulations. Two of these occur within the Serra do Barbado and Boqueirão da Onça Environmental Protection Areas (APAs), both designated as IUCN Category V protected areas under Brazilian law (SNUC – Law 9.985/2000; Brasil, 2000). Although APAs are legally protected, they allow sustainable use zoning, including extractive activities, agriculture, and infrastructure development, which makes populations of S. brachyclada more vulnerable to habitat degradation than those found in strictly protected areas (e.g., Biological Reserves, IUCN Category Ia).

The combination of: (1) a critically small AOO (< 500 km ²), (2) severe fragmentation, and (3) an observed decline in habitat quality—with ongoing threats such as illegal mining, land conversion for agriculture, and urbanization— meets the IUCN Red List criteria for Endangered (EN) under B2ab(ii,iii). Moreover, the extremely low collection frequency (0.16 records per year) and lack of adequate protection reinforce the species′ high risk of extinction.

Etymology: —The epithet brachyclada (from Greek brachys = ‘short’ + klados = ‘branch’) was chosen to emphasize the species most distinctive morphological feature: its short lateral branches bearing evident scars of deciduous leaves and stipules (brachyblasts).

Paratypes: — BRAZIL. Bahia: Abaíra , Catolés, 29 November 1999, bd. & fl., G.L. Campos et al. 201 ( HUEFS!) ; Campo Formoso , Serra dos Morgados , 819 m, 10º14′34′′S, 40º15′57′′W, 14 April 2006, bd., fl & fr., V.J. Santos 568 ( HUEFS!, SP) ; Jacobina , 11º06′S, 40º46′W, 29 August 1981, bd., fl. & fr., L.M.C. Gonçalves 144 ( HRB!, RB!) ; Lagoa Real , BA-122 (Caetité-Maniaçu), estrada para comunidade Lagoa Grande, 1024 m, 13º57′14′′S, 42º18′47,4′′W, 11 March 2022, bd. & fl., E.H. Souza et al. 1411 ( HURB!) ; Santa Terezinha , Barragem Casa Forte, 18 May 2017, bd. & fl., G. Costa et al. 2451 ( HURB!, HUEFS!) ; Umburanas , próximo ao povoado de Campo Largo , 1.093 m, 10º25′26′′S, 41º23′06′′W, 06 Feburary 2025, bd, fl. & fr., H.A. Ogasawara & G.B. Siqueira 518 ( ALCB!) .

Figures

FIGURE 1. Sida brachyclada G.Guerra. (A) Dolichoblast; (B) Brachyblast with a pseudoverticillate leaf arrangement; (C) Stipule, lateral view (left) and frontal view (right); (D) Brachyblast showing leaves and stipules scars; (E) Stellate trichome; (F) Glandular trichome; (G) Simple trichome; (H) Close-up of staminal tube; (I) Detail of glandular trichomes on filaments; (J) Mericarp, dorsal view (left) and lateral view (right); (K) Seed, lateral view. Illustration: G. Guerra.

FIGURE 2. Lankester Composite Dissection Plate (LCDP) of Sida brachyclada G.Guerra. (A) Developed lateral branch; (B) Senescent stipules; (C) Conduplicate leaf blade; (D) Glandular trichomes; (E) In sicco specimen with brachyblasts; (F) Brachyblast; (G) Terminal inflorescence; (H) Close-up of glandular trichomes on petal margins; (I) Ovary; (J) Lateral view of mericarp; (K) Dorsal view of mericarp; (L) Seed, lateral view. Photographs taken from G.Guerra 515 specimens, except E (HURB27575) and J–K (HRB04760).

FIGURE 3. Sida brachyclada G.Guerra and its natural habitat. (A) Ecotonal cerrado-caatinga shrubland at Umburanas; (B) Cerrado vegetation at Minas do Mimoso, Sento Sé; (C) Close-up of flowering branch in situ. Photographs: (A–B) G. Guerra; (C) H.A. Ogasawara.

FIGURE 4. Distribution map of Sida brachyclada G.Guerra across the altitudinal range in Bahia State, Brazil. Municipalities: (A) Sento Sé; (B) Umburanas; (C) Campo Formoso; (D) Jacobina; (E) Santa Teresinha; (F) Abaíra; (G) Lagoa Real.