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Raven's primrose-willow

narrowleaf primrose-willow

Habit Herbs slender, rarely with aerenchyma when base submerged, forming slender, glabrate stolons 10–18 cm, 0.6–1.5 mm thick, occasionally bearing flowers and fruits. Herbs slender, usually with aerenchyma near base, forming stolons 10–30 cm, 0.8–2.5 mm thick.
Stems

erect, slightly ridged, usually well branched, (15–)35–90 cm, densely hirtellous.

erect, slightly ridged, often well branched, (22–)50–100(–145) cm, glabrous or sparsely to densely, minutely strigillose.

Leaves

alternate;

stipules lanceolate to broadly deltate, 0.2–0.5 × 0.1–0.3 mm;

stolons: petiole 0.1–0.3 cm, blade elliptic to orbiculate, 1–1.8 × 0.6–1.4 cm, base attenuate, apex rounded to acute;

stems: petiole narrowly winged, 0.1–0.8 cm, blade narrowly lanceolate-elliptic, 1.3–6.5 × 0.4–1.5 cm, base attenuate, margins entire with minute hydathodal glands, apex acute, surfaces densely hirtellous;

bracts not much reduced.

alternate;

stipules narrowly ovate or lanceolate, 0.15–0.3 × 0.05–0.15 mm;

stolons: petiole attenuate, 0.2–0.5 cm, blade narrowly to very narrowly elliptic, 1–2.5 × 0.3–0.9 cm, surfaces glabrous or minutely strigillose;

stems: subsessile, blade linear to elliptic-linear, 1.6–6(–8.5) × 0.1–0.4(–0.6) cm, base very narrowly cuneate, margins entire with obscure hydathodal glands, apex very narrowly acute, surfaces glabrous or sparsely to densely, minutely strigillose or puberulent;

bracts not much reduced.

Inflorescences

leafy racemes, flowers solitary in leaf axils;

bracteoles attached near base of ovary, lanceolate or elliptic to narrowly so, (1.5–)2–4.3 ×0.3–0.9 mm, apex acuminate, surfaces hirtellous.

leafy racemes or spikes, flowers solitary in leaf axils;

bracteoles deciduous, attached on pedicel near ovary base or to 4.5 mm distal to base, linear, 0.4–4(–7.5) × 0.1–0.3 mm.

Flowers

sepals ascending-spreading, green, broadly ovate-deltate, 1.5–3 × 1.4–2.1 mm, margins entire, apex acuminate, surfaces densely hirtellous;

petals 0;

filaments light green, 0.7–1.1 mm, anthers 0.3–0.4 × 0.4–0.5 mm;

pollen shed in tetrads;

ovary obovoid to obconic, 2.8–3.5 × 2–3 mm;

nectary disc elevated 0.3–0.4 mm on ovary apex, light green, 1.4–2.5 mm diam., 4-lobed, glabrous;

style light green, 0.3–0.5 mm, glabrous, stigma clavate to subcapitate, 0.4–0.6 × 0.3–0.5 mm, not exserted beyond anthers.

sepals ascending, green, lanceolate-deltate to narrowly so, 2.5–5(–5.5) × 1–3(–3.5) mm, margins entire, apex acuminate or elongate-acuminate to cuspidate, surfaces sparsely to densely strigillose;

petals obovate to suborbiculate, 3–6 × (2–)2.5–5 mm, base attenuate, margins entire, apex obtuse;

filaments white or cream, 1.1–2.2 mm, anthers lanceolate-oblong, 1–2 × 0.6–1 mm;

pollen shed in tetrads;

ovary cylindric (wider at apex), 2.5–4.5 ×1–2.5 mm, strigillose;

nectary disc elevated (0.2–)0.3–0.6 mm on ovary apex, yellow, 1.3–2.5 mm diam., 4-lobed, margins glabrous or minutely strigillose;

style yellowish green, (0.4–)0.7–1.5 mm, glabrous or densely strigillose on proximal part, stigma clavate to subcapitate, (0.6–)1–1.9 × 0.6–0.9 mm, shallowly 4-lobed, not exserted beyond anthers.

Capsules

oblong-obovoid, subterete to scarcely 4-angled, (3–)4–5(–5.3) × 2.5–3.5(–4) mm, hard-walled, irregularly dehiscent, pedicel 0.2–0.5 mm.

elongate-obpyramidal, obscurely 4-angled, often with central, longitudinal groove on each side, 5–10(–12) × 2–5.5 mm, hard-walled, dehiscent by apical ring, pedicel 0–3.5(–5) mm.

Seeds

light brown, elliptic-oblong with slightly curved ends, 0.5–0.7 ×0.3–0.4 mm, surface cells elongate transversely to seed length.

light brown, oblong-elliptic,0.5–0.7 × 0.2–0.3 mm, surface cells oblong, elongate either parallel or transversely to seed length.

2n

= 32.

= 16.

Ludwigia ravenii

Ludwigia linearis

Phenology Flowering Jul–Sep. Flowering late Jun–Sep.
Habitat Wet, peaty habitats, ditches, margins of ponds, bogs, swamps. Drainage ditches, along river or stream banks, swales, edges of pocosins, sandy soil in wet meadows, brackish marshes, disturbed ground.
Elevation 0–100 m. (0–300 ft.) 0–300 m. (0–1000 ft.)
Distribution
from FNA
FL; NC; SC; VA
[BONAP county map]
from FNA
AL; AR; DE; FL; GA; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
[WildflowerSearch map]
[BONAP county map]
Discussion

Ludwigia ravenii is an uncommon species occurring in scattered populations in coastal southeastern Virginia and eastern North Carolina, with single disjunct populations in southeastern South Carolina and northeastern Florida. C. I. Peng (1989) observed its similarity to L. pilosa by virtue of its dense, hirtellous pubescence, but noted its smaller, more consistently autogamous flowers. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

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

Ludwigia linearis is widespread in the southeastern United States, with a complex pattern of morphological variation, especially in stem pubescence, ranging from glabrous to densely strigillose, but without strong geographical separation (C. I. Peng 1989).

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

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia
Sibling taxa
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. decurrens, L. erecta, L. glandulosa, L. grandiflora, L. hexapetala, L. hirtella, L. lanceolata, L. leptocarpa, L. linearis, L. linifolia, L. maritima, L. microcarpa, L. octovalvis, L. palustris, L. peploides, L. peruviana, L. pilosa, L. polycarpa, L. repens, L. simpsonii, L. spathulata, L. sphaerocarpa, L. suffruticosa, L. virgata
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. decurrens, L. erecta, L. glandulosa, L. grandiflora, L. hexapetala, L. hirtella, L. lanceolata, L. leptocarpa, L. linifolia, L. maritima, L. microcarpa, L. octovalvis, L. palustris, L. peploides, L. peruviana, L. pilosa, L. polycarpa, L. ravenii, L. repens, L. simpsonii, L. spathulata, L. sphaerocarpa, L. suffruticosa, L. virgata
Synonyms Isnardia linearis, L. angustifolia, L. linearis var. puberula
Name authority C. I. Peng: Syst. Bot. 9: 129, fig. 1. (1984) Walter: Fl. Carol., 89. (1788)
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