Sida, Linnaeus, 1753

Grings, Martin & Boldrini, Ilsi Iob, 2022, Synopsis of Sida (Malvoideae, Malvaceae) in the state of Rio Grande do Sul, Brazil, Phytotaxa 542 (2), pp. 105-135 : 107-108

Key to species of Sida from Rio Grande do Sul state (Adapted from Brandão et al. 2017)

1. Leaf blades entire; flowers and fruits often aggregated into terminal umbelliform inflorescences; and mericarps indehiscent ......... ......................................................................................................................................................................................... Sida linifolia

- Leaf blades crenate, irregularly serrate or basally entire (or subentire, with three teeth at the apex); flowers and fruits often solitary or aggregated into glomerules; mericarps apically dehiscent (indehiscent in S. tuberculata var. pseudo-rhombifolia)....................2

2. Stems with distichous lateral branching and leaf arrangement usually flattened; stipules subfalcate to falcate and subequal, dimorphic .....................................................................................................................................................................................................3

- Stems with alternate and helicoidal leaf arrangement; stipules linear to linear-lanceolate, equally arranged, sometimes subfalcate, but not dimorphic ...............................................................................................................................................................................4

3. Mericarps 7–8, aristae 2 mm long, flowers in axillary glomerules............................................................................ Sida planicaulis

- Mericarps 8–10, aristae 2–4 mm long, flowers in terminal glomerules............................................................................. Sida reitzii

4. Leaf blades linear, elliptic or rhomboid, basally entire, truncate, cuneate or basally rounded, and distally serrate or serrate-crenate, or subentire, with three teeth at the apex........................................................................................................................................... 5

- Leaf blades cordate, lanceolate, ovate, narrowly oblong or suborbicular, basally cordate or subcordate, and serrate-crenate throughout.........................................................................................................................................................................................14

5. Mericarps often muricate; flowers and fruits apically congested with leaves and stipules so as to appear involucellate; leaf blades basally rounded, calyx not ribbed.......................................................................................................................................................6

- Mericarps smooth in the upper portion and reticulate in the lower portion; flowers and fruits not apically congested with leaves and stipules not so as to appear involucellate; leaf blades basally rhomboid, truncate or cuneate; calyx usually 10-ribbed...................7

6. Leaf blades linear (rarely linear-lanceolate), serrate in the upper half; flowers 2 cm in diameter; fruits with 7–8 mericarps ............ ........................................................................................................................................................................................ Sida anomala

- Leaf blades cuneate-truncate, subentire, with three teeth at the apex; flowers 2.5 cm in diameter; fruits with 5 mericarps............... ...................................................................................................................................................................................... Sida paradoxa

7. Mericarps 5; stipules persistent in the stems after the leaves fall..................................................................................... Sida viarum

- Mericarps 6–14; stipules not persistent in the stems after the leaves fall ..........................................................................................8

8. Flowers in glomerules with bifid bracts ........................................................................................................................ Sida lonchitis

- Flowers solitary or in glomerules without bifid bracts.......................................................................................................................9

9. Flowers in terminal or axillary glomerules; calyx base, pedicels and veins of abaxial surface of leaves with simple trichomes ....... .................................................................................................................................................................................... Sida ramoniana

- Flowers solitary, axillary or congested in the apex of stems; calyx base, pedicels and veins of abaxial surface of leaves without simple trichomes...............................................................................................................................................................................10

10. Mericarps 6–8; calyx with simple trichomes at the apex of lobes ............................................................................ Sida tuberculata

- Mericarps 9–14; calyx without simple trichomes at the apex of lobes ............................................................................................11

11. Yellowish foliage; aristae and apex of mericarps with yellowish stellate trichomes ..................................................... Sida glaziovii

- Greenish foliage; aristae and apex of mericarps with whitish stellate trichomes.............................................................................12

12. Adaxial surface of leaf blades only with small stellate trichomes; abaxial surface farinaceous with small stellate trichomes........... ................................................................................................................................................................................... Sida rhombifolia

- Adaxial surface of leaves with simple trichomes; abaxial surface of leaves tomentose or with sparse stellate trichomes .............13

13. Leaf blades ovate-rhombic or lanceolate-rhombic; abaxial surface glabrescent, with sparse stellate trichomes and with tertiary veins forming a characteristic reticulate; mericarps aristae 1 mm long .............................................................. Sida farroupilhensis

- Leaf blades narrowly elliptic, narrowly oblong or oblong; abaxial surface tomentose, with tertiary veins not forming a reticulate; mericarps aristae greater than 1 mm long............................................................................................................... Sida potentilloides

14. Mericarps, styles and stigmas uniformly 5, the aristae, when present, with antrorse trichomes .....................................................15

- Mericarps, styles and stigmas 7 or more, the aristae, when present, with retrorse or stellate trichomes.........................................19

15. Leaf blades ovate to lanceolate (if cordate, apex not acuminate), apex acute to rounded; calyx lobes uniformly colored .............16

- Leaf blades cordate, apex acuminate; calyx lobes with dark green margins....................................................................................18

16. Prostrate herbs; leaf blades suborbicular or cordate; mericarps muticous ...................................................................... Sida confusa

- Erect subshrubs; leaf blades broadly ovate, lanceolate or narrowly oblong, subcordate; mericarps 2-spined ................................17

17. Mericarps dorsal face covered only by a hyaline membrane easily breakable ................................................................ Sida riedelii

- Mericarps dorsal face hard and reticulated, not easily breakable.................................................................................... Sida spinosa

18. Decumbent or scandent herbs; mericarps muticous or submuticous................................................................................... Sida urens

- Erect subshrubs; mericarps aristate ........................................................................................................................... Sida nemorensis

19. Mericarps muticous or submuticous; aristae up to 0.5 mm long......................................................................................................20

- Mericarps aristate; aristae greater than 0.5 mm long .......................................................................................................................21

20. Prostate or decumbent subshrubs; petals 20 mm long, yellow or pink; mericarps 4 × 2.5 mm .................................... Sida rubifolia

- Erect subshrubs; petals 10–14 mm long, pink; mericarps 3 × 2 mm ............................................................................. Sida regnellii

21. Leaf blades ovate or cordiform, rarely suborbicular, with base cordate or subcordate (rarely truncate)..................... Sida cordifolia

- Leaf blades lanceolate or narrowly oblong with base subcordate or truncate..................................................................................22

22. Petioles sulcate; leaf blades narrowly ovate, with margin undulate; calyx with trichomes 1–2 mm long; corolla orange or salmon, often with a red spot at the adaxial base of petals ................................................................................................... Sida cerradoensis

- Petioles cylindrical; leaf blades narrowly oblong, with margin not undulate; calyx with trichomes 0.5 mm long; corolla pink (rarely light yellow), without a red spot at the abaxial base of petals............................................................................................ Sida dubia