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partridge pea, sensitive partridge or wild sensitive pea, sensitive partridge pea, wild sensitive-pea

slender sensitive pea

Habit Herbs, annual, rarely over-wintering, to 0.8(–1)[–1.2] m. Stems erect, incurved ascending. Herbs, perennial, to 0.4 m. Stems usually erect, rarely procumbent, regularly branched.
Leaves

(1.5–)2–8(–9)[15–21] cm;

petiole (1.5–)2–7 mm;

extrafloral nectary 1(or 2), near mid petiole, stipitate;

leaflets (6–)8–28(–32)[–40] pairs, blades usually straight, sometimes falcate, linear, narrowly oblong, or oblong-elliptic, (3–)4–26 × 1–3 mm.

1–3.5(–4) cm;

petiole 2–4 mm;

extrafloral nectary 1(or 2), near mid petiole, rarely a second gland on rachis, sessile;

leaflets (4 or)5–10(–12) pairs, blades oblong to oblong-oblanceolate, narrowly obovate, or obliquely obovate, apex obtuse or deltate-acute, 3–12 × 1.5–0.4–6.3 mm.

Racemes

1(or 2)-flowered, axillary.

1(or 2)-flowered, axillary.

Pedicels

0.5–4[–16] mm;

bracteoles mid pedicel.

12–40(–45) mm;

bracteoles distal to mid pedicel.

Flowers

calyx greenish, sepal venation reticulate;

corolla yellow, sometimes fading pinkish, petals to 3.5–8(–9)[–16] mm;

stamens [2–]4–8[or 9];

anthers yellow-orange or red, to (1.4–)1.6–3[–9.5] mm, different sizes;

ovary usually hairy throughout, rarely glabrate.

calyx yellowish, sometimes also partly reddish, sepal venation reticulate;

corolla yellow, petals to 5–19(–20) mm;

stamens 10;

anthers yellow, to 2.5–9.5 mm;

ovary loosely hairy.

Legumes

straight, linear-oblong, [14–](15–)18–48(–56)[–78] × [2.4–]2.5–5.5(–5.8) mm.

straight, linear-oblong, 14–40(–45) × 2.5–5 mm.

Seeds

[1.9–](2.2–)2.4–3.4[–3.7] mm.

2.3–3(–3.3) mm.

Chamaecrista nictitans

Chamaecrista serpens

Distribution
from USDA
United States; Mexico; Central America; West Indies; South America (Argentina, Brazil, Paraguay, Peru)
[WildflowerSearch map]
[BONAP county map]
from USDA
Mexico; Central America; South America; s United States; West Indies
[BONAP county map]
Discussion

Varieties 13 (3 in the flora).

Chamaecrista nictitans is distinguished from the closely similar C. fasciculata (and C. deeringiana) by its globose-ovoid floral buds, which are ovoid-acuminate in the latter two species. All three varieties in the flora area belong to subsp. nictitans and are characterized by two to nine fertile stamens, while all other varieties have ten fertile stamens (they belong to the other subspecies): subsp. brachypoda (Bentham) H. S. Irwin & Barneby, subsp. disadena (Steudel) H. S. Irwin & Barneby, and subsp. patellaria (Colladon) H. S. Irwin & Barneby (H. S. Irwin and R. C. Barneby 1982). The key to varieties in the flora is adapted from Irwin and Barneby.

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

Varieties 7 (2 in the flora).

Of the seven described varieties, var. wrightii is the only one native to the flora area. Variety serpens is introduced in Florida and is the only small-flowered variety, with the longest petal to 7(–8) mm. Among the large-flowered varieties, var. delicata (Britton & Rose) H. S. Irwin & Barneby occurs locally sympatric with var. wrightii in Mexico and is distinguished from the latter by its slightly smaller flowers (the longest petal to 12 mm and the longest anther to 5.5 mm). In contrast to vars. delicata and wrightii, in the remaining large-flowered varieties, the leaves of var. grandiflora (Bentham) H. S. Irwin & Barneby, var. isthmogenes H. S. Irwin & Barneby, var. mensarum (Molina) H. S. Irwin & Barneby, and var. oaxacana H. S. Irwin & Barneby usually have only three to seven leaflets pairs.

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

Key
1. Leaflet blade margins ciliolate, some hairs 0.4+ mm; ovules 8–19.
var. leptadenia
1. Leaflet blade margins glabrous or hairs to 0.4 mm; ovules 5–10.
→ 2
2. Stems and petioles glabrous or hairs whitish, to 0.7 mm.
var. nictitans
2. Stems and petioles covered with hairs yellow or orange reddish, 1–2.5 mm.
var. aspera
1. Petals to 5–7 mm; leaflets (4 or)5–7(or 8) pairs; Florida.
var. serpens
1. Petals to 13–19(–20) mm; leaflets 7–9(–12) pairs; Arizona, New Mexico.
var. wrightii
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Caesalpinioideae (excluding Mimosoid clade) > Chamaecrista Fabaceae > subfam. Caesalpinioideae (excluding Mimosoid clade) > Chamaecrista
Sibling taxa
C. absus, C. calycioides, C. chamaecristoides, C. deeringiana, C. fasciculata, C. flexuosa, C. greggii, C. lineata, C. pilosa, C. rotundifolia, C. serpens
C. absus, C. calycioides, C. chamaecristoides, C. deeringiana, C. fasciculata, C. flexuosa, C. greggii, C. lineata, C. nictitans, C. pilosa, C. rotundifolia
Subordinate taxa
C. nictitans var. aspera, C. nictitans var. leptadenia, C. nictitans var. nictitans
C. serpens var. serpens, C. serpens var. wrightii
Synonyms Cassia nictitans Cassia serpens
Name authority (Linnaeus) Moench: Methodus, 272. (1794) (Linnaeus) Greene: Pittonia 4: 29. (1899)
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