Portulaca
Sp. Pl. 1: 445. 1753.
Gen. Pl. ed. 5, 204. 1754.
| Taxon | Illustrator ⠉ | |
|---|---|---|
 | Portulaca amilis Portulaca oleracea Portulaca pilosa | Bee F. Gunn Bee F. Gunn Bee F. Gunn |
Herbs, annual (perennial in P. suffrutescens). Roots tuberous, fleshy, fibrous, or small taproots. Stems erect to prostrate, branched, fleshy or suffrutescent; trichomes in inflorescence or stem nodes absent or present, glabrous otherwise. Leaves alternate or subopposite, congested and involucrelike immediately proximal to inflorescence; blade terete, subterete, or flattened. Inflorescences terminal in clusters, or axillary on short branches. Flowers sessile or subsessile, usually open only in sunshine; sepals broadly clasping at base, herbaceous to scarious, falling from top of capsule; petals ephemeral, 5–7, usually distinct, margins usually entire; stamens (4–) 6–40 (–100); ovary half-inferior to inferior, plurilocular proximally to 1-locular distally, placentation free-central; style 1, short, stigmas 3–8 (–18). Capsules membranaceous, chartaceous, dehiscence circumscissile. Seeds many, brown to black or gray, reniform to cochleate; seed-coat smooth or variously sculptured, granular to stellate-tuberculate or spiny. x = 4, 5, 8, 9.
Contents
Distribution
Nearly worldwide, primarily tropical and subtropical, also temperate
Discussion
Species 100–125 (10 in the flora).
Selected References
Lower Taxa
Keys
Key Based on Flowering Material
| 1 | Petals pink to purple | > 2 |
| 1 | Petals yellow, orange, copper, bronze, or white | > 6 |
| 2 | Flowers 25 mm or more diam.; petals 15 mm or longer | Portulaca grandiflora |
| 2 | Flowers to 25 mm diam.; petals 12 mm or shorter | > 3 |
| 3 | Leaf blades flattened, 2-12 mm wide, obovate to spatulate or oblanceolate | Portulaca amilis |
| 3 | Leaf blades terete to hemispheric, 0.5-3 mm wide, linear to lanceolate | > 4 |
| 4 | Petals deeply 2-lobed; stamens 40 or more; stem nodes with inconspicuous trichomes; restricted to sandstone outcrops in s Georgia | Portulaca biloba |
| 4 | Petals not 2-lobed; stamens usually fewer than 30; stem nodes with conspicuous trichomes; widespread in United States | > 5 |
| 5 | Petals medium pink to almost white; seeds 0.6 mm or more diam., elongate; restricted to granitic outcrops in Georgia, North Carolina, South Carolina, Virginia | Portulaca smallii |
| 5 | Petals dark pink to purple; seeds 0.6 mm or less diam., orbiculate; wide- spread throughout se, lower Midwest, and sw United States | Portulaca pilosa |
| 6 | Flowers 25 mm or more diam | > 7 |
| 6 | Flowers 20 mm or less diam | > 8 |
| 7 | Plants perennial; roots tuberous; stems stiffly erect; sw United States | Portulaca suffrutescens |
| 7 | Plants annual; roots fibrous; stems prostrate to suberect; widespread | Portulaca grandiflora |
| 8 | Leaf blades terete to hemispheric, linear to lanceolate, usually 3 mm or less wide | > 9 |
| 8 | Leaf blades flattened, obovate or spatulate (sometimes lanceolate in P. umbraticola), 2-15 mm or more wide | > 10 |
| 9 | Stem nodes and inflorescences with conspicuous trichomes; flowers less than 8 mm diam.; Midwest and sw United States | Portulaca halimoides |
| 9 | Stem nodes and inflorescences with inconspicuous trichomes; flowers more than 9 mm diam.; tropical Florida | Portulaca rubricaulis |
| 10 | Capsules encircled by expanded, membranaceous wing | Portulaca umbraticola |
| 10 | Capsules not winged | Portulaca oleracea |
Key Based on Fruiting Material
| 1 | Capsules each encircled by expanded, membranaceous wing | Portulaca umbraticola |
| 1 | Capsules not winged | > 2 |
| 2 | Leaf blades flattened | > 3 |
| 2 | Leaf blades terete to hemispheric | > 4 |
| 3 | Trichomes at stem nodes absent or inconspicuous; seeds 0.6-1.1 mm or more diam. | Portulaca oleracea |
| 3 | Trichomes at stem nodes conspicuous; seeds 0.4- 0.6 mm or less diam | Portulaca amilis |
| 4 | Stem nodes with inconspicuous trichomes | > 5 |
| 4 | Stem nodes with conspicuous trichomes | > 6 |
| 5 | Seeds 0.7 mm or more diam., surface cells distinctly stellate, tuberculate | Portulaca biloba |
| 5 | Seeds less than 0.7 mm diam., surface cells obscurely stellate, without tubercles | Portulaca rubricaulis |
| 6 | Seeds 0.6-1 mm diam | > 7 |
| 6 | Seeds 0.3-0.65 mm diam | > 8 |
| 7 | Longest leaves usually longer than 20 mm; capsules usually more than 4 mm diam | Portulaca grandiflora |
| 7 | Longest leaves usually shorter than 15 mm; capsules 3.5 mm or less diam. | Portulaca smallii |
| 8 | Capsules 2 mm or less diam.; lateral seed coat with densely arranged, flattened, stellate cells, tubercles absent; seeds averaging 0.5 mm or less diam. | Portulaca halimoides |
| 8 | Capsules 1.5-5 mm diam.; seed coat with loosely arranged, stellate cells; tubercles usually present; seeds averaging more than 0.5 mm diam | > 9 |
| 9 | Plants annual; roots fibrous to slightly fleshy; stems prostrate or suberect to erect | Portulaca pilosa |
| 9 | Plants perennial; roots tuberous; stems stiffly erect | Portulaca suffrutescens |