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viperina

viperina, zornia

Habit Herbs [subshrubs], perennial [annual], unarmed; roots slender.
Stems

erect, to 80 cm, glabrous or strigulose.

prostrate or erect, glabrous or pubescent, sometimes glandular-pubescent.

Leaves

stipules to 15 mm, epunctate, glabrous;

petiole 2/3 to as long as leaflets, glabrous or sparsely hairy;

leaflets 4, blades linear to narrowly elliptic, 25 × 8 mm, ± similar throughout or distal-most smaller, base cuneate, apex acute, surfaces epunctate, glabrous, abaxial midvein strigose.

alternate, even-pinnate;

stipules present, paired, peltate;

petiolate;

leaflets 2 or 4, stipels absent, blade margins entire, surfaces sometimes punctate, glabrous or pubescent.

Inflorescences

1–15-flowered, terminal or axillary, spikes, erect;

bracts present, paired, peltate, auriculate, margins ciliate;

bracteoles absent.

Spikes

1–10-flowered, crowded or ± lax, 2–17 cm;

bracts 5–7-veined, lanceolate-ovate to ovate, 10 × 7 mm, apex acute, surfaces epunctate, glabrous;

auricles 1–2.2 mm.

Flowers

calyx tube 7–10-veined, 3–4 mm, ± strigose;

corolla yellow;

banner 10–14 mm, longer than wings.

papilionaceous, chasmogamous;

calyx short-tubular, lobes 5, apex usually acute;

corolla yellow or orange-yellow;

banner longer, wider than wings;

wings not adnate to keel, auriculate;

keel subprostrate, incurved;

stamens 10, monadelphous, filaments equal;

anthers alternately dorsifixed and versatile, and sub-basifixed;

style curved, glabrous or pubescent.

Fruits

loments, stipitate [sessile], brown or tan, flattened, straight or curved, linear to oblong, indehiscent, glabrous or pubescent;

segments 2–15, breaking apart at maturity, margins ciliate, surfaces sometimes reticulate, often bristly with retrorse hairs.

Seeds

1.5–1.8 mm.

2–15, black [dark brown], compressed, ovoid.

Loments

exserted beyond bracts;

segments 2–6, 2.7–3.5 × 2.5–3.3 mm, not reticulate, eglandular, glabrous;

bristles to 1 mm.

x

= 10.

Zornia bracteata

Zornia

Phenology Flowering summer.
Habitat Sandy or gravelly soils.
Elevation 0–500 m. (0–1600 ft.)
Distribution
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; VA
[WildflowerSearch map]
[BONAP county map]
from USDA
Mexico; Central America; South America; s United States; West Indies; Asia; Africa; Indian Ocean Islands (Madagascar); Australia
[BONAP county map]
Discussion

For his Zornia bracteata, Gmelin referred to Anonymos bracteata by T. Walter (1788), an invalid name that is the basis for the epithet by Gmelin. Reports of Z. bracteata from Mexico appear to be based on a Berlandier collection (P), labeled only as “Mexico”, and is excluded from the range of the species as a doubtful record. The name Z. tetraphylla Michaux is an illegitimate later homonym and pertains here.

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

Species 75 (3 in the flora).

Zornia has traditionally been considered closely related to Stylosanthes, differing by its even-pinnate leaves without stipels and its loments with usually more than two segments. Molecular studies place Zornia closer to Adesmia de Candolle and Poiretia Ventenat in the Adesmia clade and rather distantly related to Stylosanthes (M. Lavin et al. 2001). The North American species of Zornia fall into three sections: sect. Zornia has four leaflets; sect. Isophylla Mohlenbrock has two leaflets, and the leaflets of proximal and distal leaves are essentially the same shape; sect. Anisophylla Mohlenbrock has two leaflets, and the leaflets of proximal and distal leaves differ in shape, with proximal ones usually broader and shorter, distal ones lanceolate to linear.

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

Key
1. Leaflets 4.
Z. bracteata
1. Leaflets 2.
→ 2
2. Bracts (excluding auricles) 12+ mm, crowded; loments included within bracts or exserted by 1 or 2 segments.
Z. reticulata
2. Bracts (excluding auricles) less than 12 mm, much interrupted proximally becoming crowded distally; loments exserted beyond bracts by 3–8 segments.
Z. gemella
Source FNA vol. 11. FNA vol. 11. Author: Robert H. Mohlenbrock.
Parent taxa Fabaceae > subfam. Faboideae > Zornia Fabaceae > subfam. Faboideae
Sibling taxa
Z. gemella, Z. reticulata
Subordinate taxa
Z. bracteata, Z. gemella, Z. reticulata
Name authority J. F. Gmelin: Syst. Nat. 2: 1096. (1792) J. F. Gmelin: Syst. Nat. 2: 1076, 1096. (1792)
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