FNA: Portulaca pilosa vs. Portulaca

Phenology

Flowering late spring–early fall, year-round in s Fla.

Habitat

Dry soils, beaches, disturbed habitats, roadsides and railroads on limestone, granitic, and sandstone outcrops

Elevation

0-2000 m (0-6600 ft)

Distribution

AL; AR; AZ; FL; GA; KS; LA; MO; MS; NC; NM; OK; SC; TN; TX; Mexico; Central America; South America; West Indies

[WildflowerSearch map]

[BONAP county map]

Nearly worldwide; primarily tropical and subtropical; also temperate

[BONAP county map]

Discussion

Portulaca pilosa is a highly variable species. It exhibits morphologic variability during development, with immature plants having wider (to 4 mm), longer, and flatter leaves than mature specimens. Mature leaves are narrower, shorter, and hemispheric or terete in cross section. The Linnaean drawing of the type specimen may be an immature plant. Morphologic variability also occurs in relation to habitat differences over the large geographic range of this species. Plants growing in dry habitats have the greatest density of hairs; plants growing in moist habitats are less pilose. Plants with very dense hairs on old growth will, under more moist conditions, produce new growth with fewer hairs. Growth habit is also affected by habitat. Plants growing in warm, moist environments tend to branch quickly into a spreading habit, with erect growth following secondarily. Plants in cool, dry habitats grow erect first, then branch more slowly; the plant then has a compact habit. Specimens from Alabama, Arizona, Florida, Louisiana, Mississippi, New Mexico, and Texas exhibit all morphologic conditions. Those from Arkansas, Kansas, Missouri, and Oklahoma usually occur in shallow, sandy soils, often on rocky outcrops, and are often highly branched, compact, short, and not very pilose.

(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