Sida

Linnaeus

Sp. Pl.2: 683. 1753

Gen. Pl. ed.5, 306. 1754

Common names: Fanpetals wireweed
Etymology: Greek side, name used by Theophrastos for plants now called Nymphaea alba Linnaeus
Synonyms: Dictyocarpus Malvinda Pseudomalachra
Found in FNA Volume 6. Treatment on page 310. Mentioned on page 215, 217, 239, 311.
Herbs, annual or perennial, subshrubs, or shrubs. Stems erect, ascending, or reclining to procumbent, glabrous or hairy, sometimes viscid (S. glabra). Leaves spirally arranged (distichous in S. planicaulis and S. ulmifolia), petiolate or subsessile; stipules persistent, usually linear to lanceolate or falcate; blade usually unlobed (lobed with maplelike leaves in S. hermaphrodita), base cuneate, cordate, subcordate, truncate, or rounded, margins crenate, dentate, serrate, or entire. Inflorescences axillary solitary (sometimes paired or clustered) often plicate in bud, usually 1/2 divided, often 10-ribbed at base (unribbed in S. hermaphrodita) or angulate, lobes acute or acuminate to triangular or ovate; corolla white, cream, yellow, yellow-orange, salmon-pink, red-orange, or reddish [purplish], sometimes with dark-red center; staminal column included; style 5–14-branched; stigmas capitate. Fruits developed or muticous, reticulate, glabrous or hairy, lateral walls usually persistent, indehiscent below with well-differentiated dorsal wall, indehiscent or partially dehiscent apically. Seeds 1 per mericarp, glabrous. x = 7, 8.

Distribution

North America, Mexico, West Indies, Central America, South America, Asia, Africa, Australia, warm-temperate and tropical areas.

Discussion

Species ca. 150 (19 in the flora).

In the flora area, Sida linifolia Cavanilles, flax-leaved sida, is known from a single collection (Alabama, Mobile, introduced from West Indies on ballast, Sep 1886, Mohr s.n., F) and treated here as a waif; it is distinguished from other sidas in North America by its entire leaf margins. Sida cordata (Burman f.) Borssum Waalkes has been reported in Maryland (Baltimore City); it is a generally prostrate herb with cordate leaves and filiform pedicels that are nearly the same length as the leaves; no vouchers have been found; if it was present, it can be regarded as a waif. Reports of S. aggregata K. Presl, a variable and rather common Neotropical species, have not been verified; no vouchers have been located. Sida acuta Burman f. and S. carpinifolia Linnaeus f. are names often used for ballast specimens of plants found in temperate seaports that have not persisted.

Most sidas have apical spines on the fruits that adhere to fur, wool, and clothing, and therefore it may be difficult to pinpoint their native ranges versus the areas to which they have been introduced. Some are considered to be pan-tropical roadside weeds.

Key

1 Leaf blades palmately 5–7-lobed, maplelike, to 24 cm; calyces not ribbed or angled. Sida hermaphrodita
1 Leaf blades unlobed, 1–9 cm; calyces ribbed or angled > 2
2 Stems procumbent > 3
2 Stems erect, sometimes ascending to reclining but not procumbent > 4
3 Petals white; leaves distributed evenly along stems, blade margins crenate to base; stems usually with 1–2 mm simple hairs in addition to multirayed stellate hairs; mericarps slightly rugose. Sida abutilifolia
3 Petals salmon-pink, red-orange, or yellowish; leaves crowded distally on stems, blade margins dentate only at apex; stems with appressed, normally 4-rayed stellate hairs; mericarps prominently muricate. Sida ciliaris
4 Styles 5-branched; mericarps 5; leaf blades cordate or subcordate at base > 5
4 Styles 7–14-branched; mericarps 7–14; leaf blades usually cuneate or truncate at base, sometimes rounded or subcordate to cordate > 7
5 Stems and petioles minutely stellate-hairy, hairs to 0.5 mm; petioles usually with small spinelike tubercle on stem just below its attachment. Sida spinosa
5 Stems and petioles glandular-viscid and/or with simple hairs 1–3 mm; petioles without spinelike tubercle just below attachment to stem > 6
6 Stems usually glandular-viscid; petals white or yellow-orange without darker base, not fading rose-pink; calyces usually glandular, not setose, lobes triangular, acute to short-acuminate (not beaked in bud). Sida glabra
6 Stems not glandular-viscid; petals yellowish to orange or salmon usually with dark orange or reddish base, fading rose-pink; calyces setose, not glandular, lobes trullate, attenuate-aristate (beaked in bud). Sida urens
7 Leaves and branches distichous > 8
7 Leaves spirally arranged > 9
8 Mericarps 7 or 8, spines 2 mm; inflorescences usually axillary glomerules, sometimes flowers solitary or paired; calyces 5–6 mm; staminal columns glabrous. Sida planicaulis
8 Mericarps 8–12, spines 0.5–1 mm; inflorescences axillary, flowers solitary or paired; calyces 6–8 mm; staminal columns hairy, sometimes glabrous. Sida ulmifolia
9 Leaf blades ± ovate or ovate-oblong with broadly cordate base, infrequently ovate-lanceolate to lanceolate; petioles (5–)10–25 mm > 10
9 Leaf blades rhombic to subrhombic or elliptic to oblong, sometimes oblong-lanceolate, lanceolate-elliptic, round, lanceolate, or linear; petioles 2–10(–40) mm > 11
10 Leaf blades velvety-tomentose, 1–2 times longer than wide; calyces prominently ribbed, densely stellate-tomentose; inflorescences axillary, usually corymbs or panicles, sometimes solitary flowers; fruits 6–7 mm diam.; mericarp spines to 2 mm; Alabama, Florida, Texas. Sida cordifolia
10 Leaf blades not velvety, usually 5+ times as long as wide; calyces obscurely ribbed, stellate-hairy and with long simple hairs; inflorescences axillary solitary flowers; fruits 5–6 mm diam.; mericarp spines to 1 mm; Texas. Sida tragiifolia
11 Leaf blade margins usually entire basally, distally dentate or serrate > 12
11 Leaf blade margins crenulate-serrate to dentate to base > 14
12 Pedicels 0.4–1.2 cm; leaf blades lanceolate-elliptic to round, 1.5–5 cm. Sida antillensis
12 Pedicels 0.5–4(–16) cm; leaf blades rhombic, subrhombic, or elliptic, 2.5–9 cm > 13
13 Petals yellow; stem hairs to 0.1 mm; pedicels (1–)3–4 cm. Sida rhombifolia
13 Petals cream or pale yellow with reddish spot at base; stem hairs to 0.5 mm; pedicels to 2 cm. Sida santaremensis
14 Pedicels 8–12(–16) cm. Sida longipes
14 Pedicels 0.5–6 cm > 15
15 Leaf blades narrowly oblong-lanceolate or elliptic to linear, 4–20 times as long as wide > 16
15 Leaf blades narrowly lanceolate or elliptic to subrhombic, 2.5–10 times as long as wide > 17
16 Plants usually little-branched from base; flowers little, if at all, apically congested; petals yellow-orange. Sida elliottii
16 Plants freely branching from base; flowers apically congested; petals yellow-orange to reddish, sometimes drying lavender. Sida neomexicana
17 Pedicels 2–6 cm, sometimes equaling subtending leaf; mericarps 8–10. Sida lindheimeri
17 Pedicels 0.5–3 cm, shorter than subtending leaf; mericarps 9–12 > 18
18 Pedicels unarticulated; stipules subequal to corresponding petioles. Sida littoralis
18 Pedicels articulated; stipules 2 times length of corresponding petioles. Sida rubromarginata
Facts about "Sida"
AuthorPaul A. Fryxell† + and Steven R. Hill +
Common nameFanpetals + and wireweed +
EtymologyGreek side, name used by Theophrastos for plants now called Nymphaea alba Linnaeus +
IllustratorLinny Heagy +
Referencefryxell1985a +, kearney1954a +, krapovickas2003a +, krapovickas2007a + and siedo1999a +
SynonymDictyocarpus +, Malvinda + and Pseudomalachra +
Taxon nameSida +
Taxon parentMalvaceae subfam. Malvoideae +
Taxon rankgenus +
VolumeVolume 6 +