FNA: Portulaca oleracea vs. Portulaca

Phenology

Flowering late spring–early fall.

Habitat

Fields, waste places

Elevation

0-2800 m (0-9200 ft)

Distribution

AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; ON; PE; QC; SK; Europe [Introduced in North America]

[WildflowerSearch map]

[BONAP county map]

Nearly worldwide; primarily tropical and subtropical; also temperate

[BONAP county map]

Discussion

A. P. Simopoulos and N. Salem Jr. (1986) and A. P. Simopoulos et al. (1992) have shown Portulaca oleracea to have the highest content of omega-3 fatty acids and antioxidants of any green leafy vegetable examined to date, suggesting that common purslane should be considered for its nutritional value and not for its weediness. It has long been used as fodder and may have been present in the New World in pre-Columbian times (R. Byrne and J. H. McAndrews 1975). Currently, it is fed to poultry to reduce egg cholesterol.

Portulaca oleracea is a highly variable species with worldwide distribution in temperate to warm regions and is the most winter-hardy of all the portulacas. It is a very aggressive weed, one of the ten most noxious weeds worldwide (J. S. Singh and K. P. Singh 1967). As such, many variants have been named (C. D. Legrand 1962) based on seed surface differences, size of seeds, or on variable characters of growth habit, leaf length, and number of stamens. Seven subspecies were recognized by A. Danin et al. (1978): subsp. oleracea, subsp. impolita Danin & H. G. Baker, subsp. granulatostellulata Danin & H. G. Baker, subsp. nicaraguensis Danin & H. G. Baker, subsp. nitida Danin & H. G. Baker, subsp. papillatostellulata Danin & H. G. Baker, and subsp. stellata Danin & H. G. Baker.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 100–125 (10 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key

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	P. 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	P. 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	P. 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	P. 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	P. 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	P. suffrutescens
7. Plants annual; roots fibrous; stems prostrate to suberect; widespread	P. 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	P. halimoides
9. Stem nodes and inflorescences with inconspicuous trichomes; flowers more than 9 mm diam.; tropical Florida	P. rubricaulis
10. Capsules encircled by expanded, membranaceous wing	P. umbraticola
10. Capsules not winged	P. oleracea

Key Based on Fruiting Material

1. Capsules each encircled by expanded, membranaceous wing	P. 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.	P. oleracea
3. Trichomes at stem nodes conspicuous; seeds 0.4- 0.6 mm or less diam	P. 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	P. biloba
5. Seeds less than 0.7 mm diam., surface cells obscurely stellate, without tubercles	P. 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	P. grandiflora
7. Longest leaves usually shorter than 15 mm; capsules 3.5 mm or less diam.	P. 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.	P. 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	P. pilosa
9. Plants perennial; roots tuberous; stems stiffly erect	P. suffrutescens