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7. Portulaca Linnaeus, Sp. Pl. 1: 445. 1753; Gen. Pl. ed. 5, 204. 1754.
Purslane [Latin portula, little door, in reference to the lid of the capsule]
James F. Matthews
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.
Species 100-125 (10 in the flora): nearly worldwide, primarily tropical and subtropical, also temperate.
SELECTED REFERENCES Legrand, C. D. 1962. Las especies Americanas de Portulaca. Anales Mus. Hist. Nat. Montevideo, ser. 2, 7: 1-147. Matthews, J. F. and P. A. Levins. 1985. The genus Portulaca in the southeastern United States. Castanea 50: 96-104. Walters, S. M. 1964. Portulaca. In: T. G. Tutin et al., eds. 1964-1980. Flora Europaea. 5 vols. Cambridge. Vol. 1, p. 114. Wilson, P. 1932b. Portulaca. In: N. L. Britton et al., eds. 1905+. North American Flora.... 47+ vols. New York. Vol. 21, pp 328-336.
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Key Based on Flowering Material
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| 1 |
Petals pink to purple |
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(2) |
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Petals yellow, orange, copper, bronze, or white |
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(6) |
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| 2 (1) |
Flowers 25 mm or more diam.; petals 15 mm or longer |
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3 Portulaca grandiflora (in part) |
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Flowers to 25 mm diam.; petals 12 mm or shorter |
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(3) |
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| 3 (2) |
Leaf blades flattened, 2-12 mm wide, obovate to spatulate or oblanceolate |
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1 Portulaca amilis |
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Leaf blades terete to hemispheric, 0.5-3 mm wide, linear to lanceolate |
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(4) |
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| 4 (3) |
Petals deeply 2-lobed; stamens 40 or more; stem nodes with inconspicuous trichomes; restricted to sandstone outcrops in s Georgia |
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2 Portulaca biloba |
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Petals not 2-lobed; stamens usually fewer than 30; stem nodes with conspicuous trichomes; widespread in United States |
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(5) |
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| 5 (4) |
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 |
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8 Portulaca smallii |
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Petals dark pink to purple; seeds 0.6 mm or less diam., orbiculate; wide- spread throughout se, lower Midwest, and sw United States |
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6 Portulaca pilosa |
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| 6 (1) |
Flowers 25 mm or more diam |
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(7) |
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Flowers 20 mm or less diam |
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(8) |
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| 7 (6) |
Plants perennial; roots tuberous; stems stiffly erect; sw United States |
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9 Portulaca suffrutescens |
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Plants annual; roots fibrous; stems prostrate to suberect; widespread |
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3 Portulaca grandiflora (in part) |
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| 8 (6) |
Leaf blades terete to hemispheric, linear to lanceolate, usually 3 mm or less wide |
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(9) |
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Leaf blades flattened, obovate or spatulate (sometimes lanceolate in P. umbraticola), 2-15 mm or more wide |
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(10) |
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| 9 (8) |
Stem nodes and inflorescences with conspicuous trichomes; flowers less than 8 mm diam.; Midwest and sw United States |
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4 Portulaca halimoides |
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Stem nodes and inflorescences with inconspicuous trichomes; flowers more than 9 mm diam.; tropical Florida |
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7 Portulaca rubricaulis |
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| 10 (8) |
Capsules encircled by expanded, membranaceous wing |
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10 Portulaca umbraticola |
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Capsules not winged |
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5 Portulaca oleracea |
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List of Keys
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List of lower taxa
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