FNA: Spergularia macrotheca vs. Spergularia

Distribution

CA; OR; WA; BC; including nw Mexico

Central America; Coastal and saline areas; w North America (including Mexico); w South America; Europe (Mediterranean region); Africa (Mediterranean region)

[BONAP county map]

Discussion

Varieties 3 (3 in the flora).

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

Species ca. 60 (11 in the flora).

We follow the species order of R. P. Rossbach (1940). While there have been attempts to define species groups, and sections have been described, all such efforts focus only on European-Mediterranean taxa, ignoring the many taxa endemic to South America. Likewise, the major breaks in the key to species follow Rossbach’s revision. Attempts to construct a key independent of habit were not successful; Spergularia is a difficult genus in which emphasis on seed characters appears necessary.

Spergularia is included in the first list of nomina genericorum conservanda published in 1905, conserved against Buda and Tissa. This action most likely occurred as a result of bickering between J. Britten and N. L. Britton in 1888–1890 about usage of the genera that Adanson had erected for Spergularia species with ten and five stamens respectively; see J. Britten (1890) for a summary of the arguments.

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

Key

1. Petals pink to rosy; styles 0.6-1.2 mm	var. macrotheca
1. Petals white; styles 1.2-3 mm	→ 2
2. Capsules 1.2-1.4 times as long as sepals; styles 1.2-1.9 mm	var. leucantha
2. Capsules 0.8-1 times as long as sepals; styles 2-3 mm	var. longistyla

1. Plants strongly perennial, base woody; stamens 7-10	→ 2
1. Plants annual or short-lived perennial, base not woody; stamens 1-10	→ 3
2. Seeds 0.4-0.5 mm; sepal lobes 2.5-4 mm, to 5 mm in fruit; styles 0.4-0.6 mm	S. villosa
2. Seeds (0.6-)0.7-1.2 mm; sepal lobes 4.5-7 mm, to 8 mm in fruit; styles 0.6-3 mm	S. macrotheca
3. Seeds black, not papillate	→ 4
3. Seeds light to dark brown or reddish brown, if nearly black, seeds covered with gland-tipped papillae	→ 5
4. Seeds 0.6-0.8 mm, broadly ovate, often with iridescent tinge, sculpturing of parallel, wavy lines; stipules 1-2.5 mm	S. atrosperma
4. Seeds 0.4-0.6 mm, pyriform, often with silvery, not iridescent, tinge, sculpturing of low, elongate tubercles; stipules 1.5-2 mm	S. diandra
5. Stamens 6-10	→ 6
5. Stamens 1-5	→ 8
6. Seeds 0.8-1.1 mm, ± smooth, not papillate, usually winged; capsules usually (4.5-)5.5-8 mm; plants stout; main stems usually 1-4 mm diam. proximally; leaf blades markedly fleshy	S. media
6. Seeds 0.4-0.6 mm, roughened or variously sculptured, papillate, not winged; capsules 2.8-5.4 mm; plants ± delicate; main stems usually 0.3-1 mm diam. proximally; leaf blades scarcely to somewhat fleshy	→ 7
7. Axillary leaves 2-4+ per cluster, blade scarcely fleshy; seeds reddish brown to dark brown; stipules lanceolate, apex ± long-acuminate, shiny white, conspicuous	S. rubra
7. Axillary leaves absent or 1-2 per cluster, blade at least moderately fleshy; seeds light brown; stipules mostly deltate, apex acute to short-acuminate, dull white to tan, usually inconspicuous	S. bocconi
8. Seeds 0.9-1.4 mm; capsules (1.2-)1.5-2 times as long as sepals.	S. canadensis
8. Seeds 0.3-0.7(-0.8) mm; capsules 0.9-1.5 times as long as sepals	→ 9
9. Plants glabrous; capsules 1.4-2.6 mm; sepal lobes 0.9-1.6 mm, to 2 mm in fruit; seeds 0.3-0.4 mm	S. platensis
9. Plants with stalked glands in inflorescence or throughout; capsules 2.8-6.4 mm; sepals lobes 1.8-4.5 mm, to 4.8 mm in fruit; seeds 0.5-0.7(-0.8) mm	→ 10
10. Seeds dull, not silver tinged, ± smooth; stipules longer than wide; styles 0.4-0.7 mm	S. salina
10. Seeds shiny, silver tinged, slightly roughened; stipules shorter than wide; styles 0.3-0.4 mm	S. echinosperma