Flora of North America species comparison

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Portulaca

purslane
Habit 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.

Portulaca
Distribution
from USDA
Nearly worldwide; primarily tropical and subtropical; also temperate
[BONAP county map]
Discussion

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
Source FNA vol. 4, p. 496. Author: James F. Matthews.
Parent taxa Portulacaceae
Subordinate taxa
P. amilis, P. biloba, P. grandiflora, P. halimoides, P. oleracea, P. pilosa, P. rubricaulis, P. smallii, P. suffrutescens, P. umbraticola
Name authority Linnaeus: Sp. Pl. 1: 445. (1753): Gen. Pl. ed. 5, 204. (1754)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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