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spreading sandwort

Photo is of parent taxon

spreading sandwort

Habit Plants ± strongly perennial, possibly blooming first year, not matted.
Taproots

filiform to moderately thickened;

rhizomes often present, slender, 2–15+ cm.

Stems

1–80+, erect or ascending to procumbent or prostrate to trailing, green, 5–60 cm;

internodes terete to angular, 1/3–8+ times as long as leaves, dull, retrorsely pubescent throughout or in lines, hairs minute.

often 1–10, prostrate to trailing.

Leaves

usually connate basally, with scarious sheath 0.1–0.5 mm, occasionally petiolate (proximal leaves) or sessile;

petiole 2–5 mm;

blade 1-veined, vein prominent abaxially, linear-lanceolate to narrowly elliptic or oblanceolate, 3–35 × 2–14 mm, herbaceous, margins thickened, scarious, shiny, ciliate proximally or throughout, apex obtuse or acute to apiculate, often minutely pustulate, ciliate on margins and adaxial midrib;

axillary leaf clusters absent.

Inflorescences

axillary, solitary flowers or in proliferating, mostly terminal, leafy, 1–80+-flowered cymes.

axillary, solitary flowers.

Pedicels

erect to ascending (often arcuately so), or straight to widely divergent, often hooked distally in fruit, 2–40 mm, retrorsely pubescent.

straight to widely divergent, often hooked distally in fruit, 25–40 mm.

Flowers

sepals green, 1–3-veined, 2 lateral veins 1/4–3/4 times as long as midvein, often appearing prominently keeled proximally, lanceolate to ovate (herbaceous portion oblong or lanceolate to ovate), 2–5 mm, to 5.5 mm in fruit, apex acute to acuminate, not pustulate, glabrous;

petals narrowly spatulate to obovate, 1.5–6 mm, 1/2–12/5 times as long as sepals or absent, apex obtuse to rounded, petals sometimes absent.

Capsules

± loosely to tightly enclosed by calyx, ovoid, 3–6 mm, 4/5–11/2 times as long as sepals.

Seeds

8–35, black, suborbicular, slightly compressed, 0.7–0.8 mm, shiny, smooth.

Petals

1/2–3/4 times as long as sepals or absent.

2n

= 40, 44.

= 44 (South America).

Arenaria lanuginosa

Arenaria lanuginosa var. lanuginosa

Phenology Flowering spring–summer.
Habitat Forests, limestone outcrops, moist hummocks, dunes
Elevation 0-200 m (0-700 ft)
Distribution
from FNA
AL; AZ; CA; CO; FL; GA; LA; MS; NC; NM; SC; TN; TX; UT; VA; Central America; South America
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC; TN; TX; VA; Mexico; Central America; South America
[BONAP county map]
Discussion

Varieties 4+ (2 in the flora).

Arenaria lanuginosa is morphologically diverse, both in our area and southward into northern South America, and is in serious need of comprehensive study. Other species in subg. Leiosperma (e.g., A. gypsostrata B. L. Turner) that occur in Mexico resemble A. lanuginosa; the nature of those relationships also requires study. We have taken the “conservative approach” of treating the two taxa that occur in the flora area as varieties.

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

Variety lanuginosa occurs through much of Mexico, mostly in the mountainous areas. We find material from the southeastern United States to be indistinguishable from many Mexican specimens.

Variety longipedunculata was described from two populations in Georgia and represents plants with particularly long pedicels, 40–50 mm, but this range overlaps that found otherwise in var. lanuginosa.

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

Key
1. Stems often 1-10, prostrate to trailing; inflorescences of solitary, axillary flowers; petals absent or 1/ 3/ 4 times as long as sepals
var. lanuginosa
1. Stems 1-80+, erect or ascending to procumbent; inflorescences of proliferating, leafy, 1-80+-flowered cymes; petals 3/ 2/ 5 times as long as sepals
var. saxosa
Source FNA vol. 5, p. 53. FNA vol. 5, p. 53.
Parent taxa Caryophyllaceae > subfam. Alsinoideae > Arenaria Caryophyllaceae > subfam. Alsinoideae > Arenaria > Arenaria lanuginosa
Sibling taxa
A. benthamii, A. humifusa, A. livermorensis, A. longipedunculata, A. ludens, A. paludicola, A. pseudofrigida, A. serpyllifolia
A. lanuginosa var. saxosa
Subordinate taxa
A. lanuginosa var. lanuginosa, A. lanuginosa var. saxosa
Synonyms Spergulastrum lanuginosum A. lanuginosa var. longipedunculata
Name authority (Michaux) Rohrbach: in C. F. P. von Martius et al., Fl. Bras. 14(2): 274. (1872) unknown
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