Contains 17 accepted taxa overall.

Characteristics
Persicaria Mill.
SMARTWEED
Classification
-
-
-
CARYOPHYLLALES
Persicaria
Citation
PERSICARIA (Linnaeus) Miller, Gard. Dict. Abr., ed. 4. 1754.
BASIONYM: Polygonum Linnaeus, sect. Persicaria Linnaeus, Sp. Pl. 360. 1753.
TYPE: Persicaria maculosa Gray 1821. (Polygonum persicaria Linnaeus 1753.) Typified by Britton & A. Brown, Ill. Fl. N. U.S., ed. 2. 1: 665. 1913.
Species
Scientific Name Common Name Herbarium Specimens Status Photos
Persicaria amphibia ssp. laevimarginata Water Smartweed
Persicaria arifolia Halberd-leaf Tearthumb
Persicaria densiflora Dense-flower Smartweed
Persicaria extremiorientalis East Asian Smartweed
Persicaria hirsuta Hairy Smartweed
Persicaria hydropiper Common Smartweed, Waterpepper, Marshpepper Smartweed
Persicaria hydropiperoides Waterpepper
Persicaria lapathifolia Willow-weed, Dockleaf Smartweed, Pale Smartweed
Persicaria longiseta Longbristle Smartweed, Bristly Lady’s-thumb
Persicaria maculosa Lady's-thumb, Heart's-ease
Persicaria meisneriana var. beyrichiana Mexican Tearthumb
Persicaria orientalis Kiss-me-over-the-garden-gate, Prince's-feather, Prince's-plume
Persicaria pensylvanica Pinkweed, Common Smartweed, Pennsylvania Smartweed
Persicaria punctata Dotted Smartweed
Persicaria sagittata Arrowleaf Tearthumb, Arrowvine, Scratch-grass
Persicaria setacea Swamp Smartweed
Persicaria virginiana Jumpseed
Identification Key
1.  Stems with recurved prickles
2
1.  Stems without prickles
4
2.  Leaf blade broadly hastate, hastate-cordate, to triangular; tepals 4
2.  Leaf blade linear-lanceolate to oblong; tepals 5
3
3.  Leaves subsessile to sessile, the blade base cordate, truncate, to cuneate; peduncle glandular-stipitate, at least distally
3.  Leaves petiolate (becoming subsessile distally), the blade base cordate to sagittate; peduncle eglandular
4.  Styles exserted, persistent on achenes; inflorescences spikelike, interrupted
4.  Styles included, rarely exserted, deciduous; inflorescences capitate, paniclelike, or spikelike, uninterrupted or interrupted
5
5.  Petiole winged, auriculate; inflorescence capitate
5.  Petiole not winged nor auriculate; inflorescence spiciform
6
6.  Ocrea eciliate or the cilia <0.5 mm long
7
6.  Ocrea ciliate with bristles 1-12 mm long
9
7.  Rhizomatous perennial; peduncles glabrous to sparsely setose below the flowers; achene biconvex
7.  Annual; peduncles usually stipitate-glandular; achene discoid or concave
8
8.  Inflorescence usually arching or nodding; tepals usually 4; outer tepals with prominent distally bifurcate anchor-shaped veins
8.  Inflorescence usually erect; tepals usually 5; outer tepals without anchor-shaped veins
9.  Upper stem and peduncles stipitate-glandular
9.  Upper stem and peduncles not stipitate-glandular
10
10.  Stem hirsute, at least near the inflorescence
11
10.  Stem glabrous to appressed pubescent
12
11.  Ocrea without a broad herbaceous flange; petiole 0.1-0.3 cm long; leaf blades linear-lanceolate
11.  Ocrea with a broad green-herbaceous flange; petiole 1-9 cm long; leaf blades broadly ovate
12.  Tepals uniformly glandular-punctate
12.  Tepals not glandular, or rarely sparse on the base of inner tepals
13
13.  Annual; ocreolae of the inflorescence not overlapping, or only overlapping distally
14
13.  Rhizomatous perennial; ocreolae of the inflorescence overlapping
15
14.  Ocrea surface with stiff ascending-appressed hairs, the cilia at the apex 1-7 mm long; leaf blade 0.5-2 cm wide, the upper surface glabrous; tepals white, pink, to greenish
14.  Ocrea surface with flexuous spreading hairs, the cilia at the apex 5-15 mm long; leaf blades 1.5-4 cm wide, the upper surface puberulent when young; tepals white
15.  Inflorescence ocreolae (0.5)1-4(6) mm long, subequal to the tube
15.  Inflorescence ocreolae 0.2-1.3(2) mm long, shorter than the tube
Genus Synonyms
Synonym Full Citation Basionym Type
No synonyms found.