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FNA | Family List | FNA Vol. 4 | Portulacaceae

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

Portulaca oleracea

Credit: Harvard University Herbaria

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.


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.

Key Based on Fruiting Material

1 Capsules each encircled by expanded, membranaceous wing   10 Portulaca umbraticola
+ Capsules not winged   (2)
2 (1) Leaf blades flattened   (3)
+ Leaf blades terete to hemispheric   (4)
3 (2) Trichomes at stem nodes absent or inconspicuous; seeds 0.6-1.1 mm or more diam.   5 Portulaca oleracea
+ Trichomes at stem nodes conspicuous; seeds 0.4- 0.6 mm or less diam   1 Portulaca amilis
4 (2) Stem nodes with inconspicuous trichomes   (5)
+ Stem nodes with conspicuous trichomes   (6)
5 (4) Seeds 0.7 mm or more diam., surface cells distinctly stellate, tuberculate   2 Portulaca biloba
+ Seeds less than 0.7 mm diam., surface cells obscurely stellate, without tubercles   7 Portulaca rubricaulis
6 (4) Seeds 0.6-1 mm diam   (7)
+ Seeds 0.3-0.65 mm diam   (8)
7 (6) Longest leaves usually longer than 20 mm; capsules usually more than 4 mm diam   3 Portulaca grandiflora
+ Longest leaves usually shorter than 15 mm; capsules 3.5 mm or less diam.   8 Portulaca smallii
8 (6) 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.   4 Portulaca halimoides
+ 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 (8) Plants annual; roots fibrous to slightly fleshy; stems prostrate or suberect to erect   6 Portulaca pilosa
+ Plants perennial; roots tuberous; stems stiffly erect   9 Portulaca suffrutescens

List of Keys

  • List of lower taxa


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