Sida ellipticifolia Baracho & Agra, 2025

Baracho, George Sidney, Filho, Everton De Amorim Freitas & Agra, Maria De Fátima, 2025, New and endemic species of Sida sect. Ellipticifoliae (Malvaceae, Malveae) from Brazil and an updated key to the species of this section, Phytotaxa 704 (3), pp. 283-292 : 285-290

Sida ellipticifolia Baracho & Agra , sp. nov. ( Figs. 1 , 2A , Table 1)

Similar to Sida littoralis Siedo (2014: 1 , Fig. 2B ) by the leaf blade morphology, the upper surface smooth pubescent with minute multiradiate trichomes [which Siedo (op.cit.) refers as stellate], stipules slightly exceeding the petiole, arrangement of the flowers along the branches, calyx accrescent in fruit, longitudinally 10-ribbed, and mericarps (9)10–12, strongly reticulated dorso-laterally, but differs in habit, morphology of the stipules, simple trichomes mixed in the indumentum of the stem and branches or, when present, isolated on the lower surface of the leaf blade, basally obtuse to subcordate leaves, articulate pedicel, corolla diameter, lozenge-shaped sepals, apical portion of the schizocarp not emergent from calyx, forked trichomes mixed in the indumentum of the staminal column, and ornamentation of the mericarps ( Table 1).

TYPE:— BRAZIL. Paraíba: João Pessoa, Engenho Velho, nas imediações da Granja Santa Júlia, 7º34’S, 34º90’W, 9.5–13.5 m, 11 September 2020 (fl., fr.), Baracho 2242 (holotype JPB, isotype UFP).

Erect herbs 40–100 cm tall, stems and branches pubescent, with minute stellate multiradiate trichomes, 8–16 rayed, mixed with longer, sparse simple trichomes. Stipules 4.5–8.5 × 0.8–1.5 mm, 1–2-nerved, narrowly lanceolate to smooth subulate, asymmetric, glabrescent with minute sparse stellate multiradiate trichomes sometimes mixed with sparse ciliate simple trichomes, slightly exceeding the petiole. Petiole 3–5 mm long, cylindrical to slightly compressed, stellate multiradiate pubescent. Leaf blades 2.0–6.0 × 0.6–1.0 cm, symmetric, concolor, elliptic to elliptic-lanceolate, basally obtuse to subcordate, 3–(6)-nerved, margin irregularly dentate to base, apex acute or sometimes acuminate, glabrous to glabrescent; the upper surface smooth pubescent with minute stellate multiradiate trichomes; the lower surface rarely with minute simple trichomes. Inflorescences solitary and axillary to terminal. Flowers solitary in the leaf axils or congested apically through shortened internodes; axillary pedicels c. ½ shorter than the adjacent petiole, articulated c. 2 mm long below the calyx, glabrous to glabrescent, minute multiradiate pubescent. Calyx 7.0–8.0 × 5.0–7.0 mm, pyramidal-pentangular, not accrescent when flowering or accrescent in fruiting, prominently 10-ribbed, glabrescent, the simple trichomes more frequently on lacinae, greenish; lozenge-shaped sepals, the lobes 4.0–5.0 × 4.2–5.0 mm, acuminate, apex sometimes caudate and recurved on the fruit, internally glabrous. Corolla 8–10 mm in diameter; petals c. 8.0 × 4.5–6.5 mm, oboval, asymmetric, usually with slightly greenish-yellow center, margin sparsely ciliate and slightly pilose at base; stamens 25–30, free filaments c. 0.5 mm, sparsely pilose and organized into 4–5 phalanges, staminal column c. 1.5 mm long, cylindric, yellowish, with simple and forked minute trichomes; ovary 1.0– 1.5 × 1.8–2.0 mm, compressed, glabrous, carpels (9)10–12, free styles (9)10–12, c. 1 mm long, cylindrical, recurving at anthesis, greenish-yellow, stigma capitate, greenish-yellow. Schizocarp 3.6–4.0 mm long, with apical portion not emerging from the calyx, oblate. Mericarps (9)10–12, 3.0–3.8 × 2.0–2.8 × 1.2–1.5 mm, brownish; apical zone 0.5–0.6 mm long, dark brown, the aristae 0.5–1.0 mm long, glabrescent and sparsely covered with simple minute trichomes, the external walls smooth, internal walls dehiscent; basal zone 1.5–1.8 mm long, dorsal wall rounded and oblong, strongly reticulate and carinate, glabrous or pubescent on apical portion; lateral walls strongly reticulate, semicircular; seeds 1.5–2.0 × 1.5–2.0 × 0.8–1.2 mm, trigonous-reniform, smooth, blackish, hilum pubescent. Columella 1.5 mm long, persistent.

Etymology: —The epithet refers to section Ellipticifoliae , to which the new species has been inserted.

Discussion: — Sida is an unwieldy genus. The artificiality of Fryxell’s infrageneric classification (1985 and Krapovickas 2003, for sect. Distichifoliae) has been corroborated by molecular studies by Fuertes et al. (2003) and Pejhanmehr (2022). However, although these studies are potentially enlightening for the phylogenetic understanding of the genus, they are still not entirely sufficient to abandon the current sectional classification, given that some sections adopted by Fryxell (1985), as well as being morphologically distinct, have been shown to be monophyletic. Sida ellipticifolia is the first new endemic species of Sida sect. Ellipticifoliae from Brazil and represents the first local record of a native specimen of this section, which was previously reported by Bovini (2017) for the state of Paraná ( Fig. 3 ) with the occurrence of S. elliottii Torrey & Gray (1838: 231) var. elliottii , an invasive species of pasture areas which, according to the author, was accidentally introduced into southern Brazil by the importation of agricultural products from the USA. The most distinctive characters of S. ellipticifolia are the simple trichomes mixed in the indumentum of the stem and branches, obtuse leaf base, short and articulated pedicel, lozenge-shaped sepals, and apical portion of the schizocarp not emerging from the calyx, which together are not observed in the other species of this section. Of these, the new species is more similar to S. littoralis from Florida ( Fig. 2B ; 3 ), which may be its closest relative and with which it shares the following attributes: morphology of the leaf blade, the pubescent smooth upper surface with tiny multiradiate trichomes [which Siedo (2014) refers to as stellate], stipules that slightly exceed the petiole, arrangement of the flowers along the branches, calyx accrescent in fruit, longitudinally 10-ribbed, and mericarps (9)10-12, strongly reticulated dorso-laterally. S. ellipticifolia is the tenth species in its section. In addition, both updated distribution map and identification key for the species Sida sect. Ellipticifoliae are provided below ( Fig. 3 ).

Distribution and ecology: —The new species is endemic to the far east of the Americas, in north-eastern Brazil, and has been recorded in the Littoral zone of the municipality of João Pessoa, in the state of Paraíba ( Fig. 2C ), in ruderal and disturbed forest areas, occurring at sea level elevations of between 9.5 and 13 m. Sida ellipticifolia and S. littoralis are Neotropical species separated geographically by a gap of 6,500 km. However, although morphologically related, both have almost the same ecological similarity. They are endemic to remnant vegetation in coastal areas and grow preferentially on siliceous substrates of gravel and sand. Harshberger (1914) had already pointed out similarities between the floras of southern Florida and South America, while Cramer (1971) suggested a close palaeogeographical relationship between this American state and northern Brazil and north-eastern Africa. Therefore, reporting taxonomic affinities between two geographically distant species and affirming Brazil as the centre of native occurrence of Sida sect. Ellipticifoliae are not such surprising conclusions.

Conservation Status: — Sida ellipticifolia has a very restricted extent of occurrence (EOO= 0,000 km 2,CR) and area of occupation (AOO= 4,000 km 2, CR), having only been reported in a single locality in the Littoral phytogeographical zone in Paraíba, Brazil. Although there are forest fragments mixed with sandy soils of restinga vegetation in this area, the specimens were collected in plantation areas, ruderal sites or wastelands, growing in sandy and gravel soils. Therefore, according to the IUCN criteria (2024), S. ellipticifolia is assessed as endangered [(CR B1abB2abE].

Key to species of Sida sect. Ellipticifoliae (adapted from Fryxell 1985 and Siedo 2014)

1. Stems and branches with internodes notably shortened apically; stipules ½ to approximately three times the length of the adjacent petiole; leaves unlobed and never entire, linear to elliptic or elliptic-lanceolate, usually dentate or serrate throughout, attenuate, obtuse, truncate or rarely subcordate at base........................................................................................................................................ 2, sect. Ellipticifoliae [western Texas and southestern USA, north Mexico to Honduras, Bahamas ( S. rubromarginata ?) and Brazil]

1. Stems and branches with internodes constant or gradually shortening towards the apex; stipules ½ to 45 times smaller than the adjacent petiole; leaves sometimes lobed or entire (or shallowly so), variously shaped, ¼ to distally crenate, dentate or serrate, cuneate, rhomboid or cordate at base ....................remaining Sida [pantropical and tropical regions and adjacent temperate zones]

2. Pedicels up to 15–20 cm long, 1.5–4 times as long as subtending leaves..........................................................................................3

2. Pedicels no more than 6 cm long, shorter than or only slightly exceeding subtending leaves ..........................................................4

3. Leaves serrate, linear to lance-linear, leaf blades 6–20 times as long as wide; petals pale orange to orange-red; mericarps moderately to prominently reticulated dorso-laterally on lower portion, walls sometimes disintegrating, appearing membranaceous ................ ........................................................................ Sida longipes Gray (1852: 19) [north and northeast Mexico to western Texas, USA]

3. Leaves serrate, broadly to narrowly elliptic, leaf blades 1.5–2 times as long as wide; petals pale yellow to orange-yellow; mericarps weakly reticulated dorso-laterally on lower portion, but not disintegrating ........................................................................................ ....................................... Sida potosina Brandegee (1911: 184) [endemic to San Luis Potosí and Tamaulipas, in northeast Mexico]

4. Leaf blades narrowly to broadly oblong or elliptic, apically obtuse, rounded or weakly acute; mericarps blunt, rounded to two-awned apically ....................................................................................................................................................................................5

4. Leaf blades linear or lance-linear to narrowly elliptic or rhombo-elliptic, apically acute to acuminate; mericarps weakly to prominently two-awned apically ........................................................................................................................................................6

5. Plant decumbent to ascending; leaf blades serrate, narrowly elliptic, 2-6 times as long as wide; upper surface with short multiradiate hairs, occasionally mixed with simple hairs; mericarps smooth to weakly reticulate dorso-laterally in the basal portion ................. Sida linearis Cavanilles (1797: 6) [endemic to north-central to southern Mexico, between the states of Durango and Chiapas]

5. Plant erect; leaf blades toothed, elliptic to ovate, 1.5 to 2 times longer than wide, upper surface usually glabrous or sometimes with sparse, simple hairs; mericarps smooth dorso-laterally in the basal portion............................................................. Sida turneroides Standley (1940: 90) [endemic from the north to the east-central part of Mexico, between the states of Coahuila and Hidalgo]

6. Leaf blades narrowly rhombo-elliptic; stipules approximately twice the length of the adjacent petiole, linear; seeds pubescent ventro-apically............................................................................................................................... Sida rubromarginata Nash (1896: 102) [ USA, from the northeast Atlantic coast to west-central Florida, on the coast of the Gulf of Mexico, and in the Bahamas (?)]

6. Leaf blades linear to linear-elliptic, lanceolate or elliptic-lanceolate, narrowly elliptic or elliptic; stipules ½ to slightly higher than the adjacent petiole, falcate or subulate, non-linear; seeds glabrous or rarely puberulent ventro-apically........................................7

7. Leaf blades linear to lanceolate; axillary pedicels approximately equal to or slightly larger than the adjacent petiole, articulated 10–20 mm below the calyx; mericarps with membranaceous to slightly disintegrated walls ............................................................. ....................................................................................................................................... Sida lindheimeri Engelmann & Gray (1845: 213) [north and northeast Mexico to the USA, from the far south to central-east and northeast Texas and southwest Louisiana]

7. Leaf blades linear-elliptic or elliptic-lanceolate to narrowly elliptic or elliptic; axillary pedicels about ½ shorter or approximately equal to the adjacent petiole, non-articulated or, if articulated, about 2 mm below the calyx; mericarps with smooth to reticulated walls....................................................................................................................................................................................................8

8. Leaf blades crenulate-serrate to dentate or serrate, lower surface with conspicuous venation; stipules approximately equal to or slightly higher than the adjacent petiole; calyx lobes apically acuminate or slightly caudate ...........................................................9

8. Leaf blades serrated, lower surface with non-conspicuous venation; stipules ½ to approximately equal to the adjacent petiole; calyx lobes apically acute to weakly acuminate ........................................................................................................................................10

9. Herbs 1–2 m tall, leaf blades linear-elliptic to narrowly elliptic, sometimes weakly rhombiform, basally cuneate; pedicel non-articulated; trullate-shaped sepals; apical portion of the schizocarp emerging from the calyx............................................................ ................ Sida littoralis Siedo [endemic to southwest Florida, Gulf coast, between La Costa and Captiva islands, in Lee County]

9. Herbs 0.4–1 m tall; leaf blades elliptic to elliptic-lanceolate, basally obtuse to subcordate, the lower surface rarely with minute simple trichomes; pedicel articulated, lozenge-shaped sepals; apical portion of the schizocarp not emerging from the calyx .......... ...................................................................... Sida ellipticifolia Baracho & Agra [endemic to the state of Paraíba, northeast Brazil]

10. Plant decumbent to ascendant, diffusely branched basally; leaves with pubescent upper surface, the multiradiate trichomes sometimes mixed with single hairs; mericarps smooth to weakly reticulate dorso-laterally in the basal portion........................................................ Sida neomexicana Gray (1887: 296) [from Arizona and New Mexico, in the southwest of the USA, to the far west of Texas and towards Sonora, northwest Mexico to the north-east of the country, in San Luis Potosí]

10. Plant erect, not diffusely branched at the base; leaves with a glabrous or, less commonly, pubescent upper surface, the minute trichomes multiradiate and/or simple; mericarps moderately to strongly reticulate dorso-laterally on the basal portion ...............11

11. Upper leaf surface glabrescent to moderately pubescent with simple and/or multirradiate trichomes; flowers weakly congested apically; calyx with longer villous trichomes at base and along costae ............................. Sida elliottii Torr. & A. Gray var. elliottii [from southeast Missouri and south Virginia, extending through the southeast United States to north Florida, and southern Brazil]

11. Upper leaf surface glabrous; flowers not apically congested; calyx with villous trichomes absent ......................... Sida elliottii var. parviflora Chapman (1897: 48) [central and southern Florida and the coastal zone from Texas to Mexico, Guatemala and Honduras]

Figures

FIGURE 1.A–N: Sida ellipticifolia. A: habit; B: leaf apex; C: leaf base; D: stipule; E: calyx in fruiting with articulated pedicel; F: corolla in final anthesis; G: schizocarp with mature mericarps; H: detail of the stipules equal to or slightly exceeding the petiole; I: detail of the schizocarp not emerging from the calyx; J: column of stamens organised into phalanges; K: gynoecium; L: mericarp, dorsal view; M: mericarp, lateral view with strong reticulation; N: seed with pubescent hyle. A, H, bar = 1 cm; B, C, E-G, I–K, bar = 2 mm; D, L–N, bar = 1 mm. Photos: G.S. Baracho.

FIGURE 2. A. Holotype of Sida ellipticifolia at the Lauro Pires Xavier Herbarium, João Pessoa, PB, Brazil (JPB). B. Holotype of S. littoralis (as “floridana”) at The Harvard University Herbaria (GH), Cambridge, MA, United States, Specimen 00219326, https://kiki.huh. harvard.edu/databases/specimen_search.php?mode=details&id=152786.

FIGURE 3. Summary of geographic distribution of Sida sect. Ellipticifoliae based in Siedo (1999) and Villaseñor et al. (2016).