font settings and languages

Font Size: Large | Normal | Small
Font Face: Verdana | Geneva | Georgia
Languages:

Polygonum hickmanii

(Hickman's Knotweed)

Overview

[ Back to top ]

Endangered

Threat status

Interesting Facts

[ Back to top ]
 

Common Names

[ Back to top ]

Common Names in English:

Hickman's Knotweed, Hickman´s Knotweed

Description

[ Back to top ]

Family Polygonaceae

Herbs, shrubs , or small trees , sometimes monoecious or dioecious. Stems erect , prostrate , twining , or scandent , often with swollen nodes, striate , grooved , or prickly. Leaves simple , alternate, rarely opposite or whorled , petiolate or subsessile ; stipules often united to a sheath (ocrea) . Inflorescence terminal or axillary , spicate , racemose, paniculate , or capitate. Pedicel occasionally articulate . Flowers small, actinomorphic , bisexual , rarely unisexual . Perianth 3-6-merous, in 1 or 2 series, herbaceous, often enlarged in fruit or inner tepals enlarged, with wings , tubercles , or spines. Stamens usually (3-) 6-9, rarely more; filaments free or united at base ; anthers 2-loculed, opening lengthwise; disk annular (often lobed ) . Ovary superior, 1-loculed; styles 2 or 3, rarely 4, free or connate at lower part. Fruit a trigonous , biconvex , or biconcave achene; seed with straight or curved embryo and copious endosperm.

About 50 genera and 1120 species: worldwide, but primarily N temperate with a few species in tropical regions ; 13 genera (two endemic) and 238 species (65 endemic) in China.[1]

Genus Polygonum

Herbs, shrubs , or subshrubs , annual (perennial in P. striatulum), homophyllous or heterophyllous , sometimes heterocarpic; roots fibrous or woody. Stems prostrate to erect , glabrous , smooth or sometimes papillous-scabridulous. Leaves cauline, alternate (opposite in P. humifusum), petiolate or sessile; ocrea with distal part persistent , often hyaline , white or silvery, 2-lobed, chartaceous , glabrous, disintegrating into fibers, or disintegrating completely; petiole base articulated with ocrea or not; blade linear , lanceolate, elliptic , ovate , or subround, margins entire. Inflorescences axillary or axillary and terminal , spikelike, or flowers solitary; peduncle absent. Pedicels present or absent. Flowers bisexual , 1-7(-10) per ocreate fascicle, base not stipelike; perianth nonaccrescent, white or greenish white to pink, campanulate to urceolate , glabrous; tepals 5, connate 3-70% of their length , petaloid or sepaloid , monomorphic or, rarely, dimorphic , the inner usually flat, the outer flat or sometimes keeled and cucullate distally, sometimes of different length than the inner; stamens 3-8 (some may be reduced to staminodes) ; filaments distinct , free or adnate to perianth tube, glabrous; anthers whitish yellow, pink to purple or orange-pink, elliptic to oblong ; styles (2-) 3, mostly spreading , distinct or connate proximally; stigmas 2-3, capitate. Achenes included or exserted, yellow-green, brown, or black, unwinged, (2-) 3-gonous, glabrous. Seeds: embryo curved . x = 10.

Species ca. 65: nearly worldwide.

Two sections of Polygonum are recognized here. Section Polygonum is nearly cosmopolitan and best represented in north-temperate regions; sect. Duravia comprises species restricted to North America. K . Haraldson (1978) recognized both sections based on differences in stem morphology, petiole structure, and pollen morphology. J. C. Hickman (1984) described sect. Monticola and included in it species of sect. Duravia occurring mostly in montane habitats , with leaves articulated to the ocreae, one-veined, and not mucronate , proximal leaves lanceolate to round , and styles connate at their bases and neither hardened nor persistent. L.-P. Ronse Decraene and J. R. Akeroyd (1988) and L.-P. Ronse Decraene et al. (2000) included sect. Duravia in sect. Polygonum based on floral and fruit characters.

Similarities in floral structure, fruit anatomy, and pollen morphology have been noted between Polygonella with Polygonum (L.-P. Ronse Decraene et al. 2000). Based on evidence from comparative morphological studies, Ronse Decraene et al. (2004) included Polygonella in sect. Duravia of Polygonum.

Four introduced taxa of sect. Polygonum that were collected in the flora area at the end of the nineteenth century and beginning of the twentieth century appear not to have persisted here and are not included in the keys . Polygonum arenarium Waldstein & Kitaibel and P. bellardii Allioni were reported by B . L. Robinson (1902) from Rhode Island and Massachusetts, respectively. The former resembles P. patulum but has open flowers. Polygonum bellardii is discussed below under P. ramosissimum. Polygonum polycnemoides Jaubert & Spach and P. humifusum C. Merck ex K. Koch subsp. humifusum were reported by J. F. Brenckle (1941). The former was collected in New York City in 1894 and in Idaho in 1940. It differs from all other Polygonum species in having a tube 55-70% of the perianth length. Polygonum humifusum subsp. humifusum is discussed below under P. humifusum subsp. caurianum.[2]

Physical Description

Species Polygonum hickmanii

Herbs, compact , often cushion-like. Stems erect , color unknown, simple to profusely branched from near base , not wiry, 2-5 cm, glabrous . Leaves persistence and crowded at brance tips , not articulated to ocreae; ocrea 4-6 mm, glabrous, proximal part cylindric , distal part silvery, disintegrating nearly to base into straight fibers; petiole absent; blade 3-veined, without pleats, linear , 5-35 × 1-1.5 mm, margins revolute , smooth , apex acuminate. Inflorescences axillary ; cymes insertion unknown, 1-flowered. Pedicels absent. Flowers closed ; perianth 2-3 mm; tube 6-18 % of perianth length, tepals imbrication unknown, white with whitish or pink margins, petaloid , oblong , apex acute, mucronate ; midveins unbranched; stamens 8; anthers orange-pink. Achenes enclosed in perianth, olive brown, ovate , 2-2.3 mm, faces subequal , shiny, smooth. [source]

The above description is based on the original one by Hinds and Morgan. [source]

Habit: Forb/herb

Flowers: Bloom Period: May, June, July, August, September, October.

Habitat

Open, seasonally dry grasslands; of conservation concern; 200-300 m [3].

Biology

[ Back to top ]

Reproduction

Duration: Annual

Taxonomy

[ Back to top ]

Notes

Name Status: Accepted Name .

Last scrutiny: 15-Mar-2000

Similar Species

[ Back to top ]

Members of the genus Polygonum

ZipcodeZoo has pages for 134 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

P. achoreum (Leathery Knotweed) · P. acuminatum (Tapertip Smartweed) · P. affine (Himalayan Fleece Flower) · P. alpinum (Alaska Wild Rhubarb) · P. amphibium (Longroot Smartweed) · P. amphibium var. emersum (Longroot Smartweed) · P. amphibium var. stipulaceum (Swamp Smartweed) · P. arenarium (European Knotweed) · P. arenastrum (Common Knotweed) · P. argyrocoleon (Persian Knotweed) · P. arifolium (Halberdleaf Tearthumb) · P. aubertii (Chinese Fleecevine) · P. aubertii 'Lemon Lace' (Silverlace Vine) · P. aviculare (Birdgrass) · P. aviculare angustissimum (Prostrate Knotweed) · P. aviculare aviculare (Prostrate Knotweed) · P. aviculare neglectum (Prostrate Knotweed) · P. baldschuanicum (Bukhara Fleeceflower) · P. bellardii (Narrowleaf Knotweed) · P. bidwelliae (Bidwell's Knotweed) · P. bistorta (Meadow Bistort) · P. bistorta carneum (Meadow Bistort) · P. bistorta var. bistorta (Meadow Bistort) · P. bistorta var. plumosum (Meadow Bistort) · P. bistorta 'Superbum' (European Bistort) · P. bistortoides (American Bistort) · P. bohemicum (Bohemian Knotweed) · P. bolanderi (Bolander's Knotweed) · P. boreale (Northern Knotweed) · P. bungeanum (Bunge's Smartweed) · P. buxiforme (Box Knotweed) · P. caespitosum (Bristled Knotweed) · P. caespitosum var. caespitosum (Oriental Ladysthumb) · P. caespitosum var. longisetum (Oriental Ladysthumb) · P. californicum (California Knotweed) · P. campanulatum (Bellflower Smartweed) · P. capathifolium (Grey Moray) · P. capitatum (Pink Knotweed) · P. careyi (Carey's Smartweed) · P. cascadense (Cascade Knotweed) · P. caurianum (Alaska Knotweed) · P. chinense (Chinese Knotweed) · P. cilinode (Fringed Black Bindweed) · P. convolvulus (Black Bindweed) · P. convolvulus var. convolvulus (Knot Grass) · P. convolvulus var. subulatum (Wild Buckwheat) · P. cuspidatum 'Crimson Beauty' (False Bamboo) · P. cuspidatum 'Devon Cream' (False Bamboo) · P. cuspidatum 'Freckles' (Speckled Mexican Bamboo) · P. cuspidatum 'Variegata' (Speckled Mexican Bamboo) · P. davisiae (Davis' Knotweed) · P. densiflorum (Denseflower Knotweed) · P. douglasii (Douglas Knotweed) · P. douglasii nuttalii (Douglas´s Knotweed) · P. douglasii var. douglasii (Douglas´s Knotweed) · P. douglasii subsp. austiniae (Austin's Knotweed) · P. douglasii subsp. engelmannii (Engelmann's Knotweed) · P. douglasii subsp. johnstonii (Johnston's Knotweed) · P. douglasii subsp. majus (Large Knotweed) · P. douglasii subsp. nuttallii (Nuttall's Knotweed) · P. douglasii subsp. spergulariiforme (Scatter Knotweed) · P. emersum (Longroot Smartweed) · P. equisetiforme (Horsetail Knotgrass) · P. erectum (Devil's Shoestring) · P. fowleri (Fowler's Knotweed) · P. franktonii (Nova Scotia Knotweed) · P. glaucum (Seaside Knotweed) · P. herniarioides (Knotweed) · P. heterosepalum (Oddsepal Knotweed) · P. hickmanii (Hickman's Knotweed) · P. hirsutum (Hairy Smartweed) · P. hydropiper (Annual Smartweed) · P. hydropiperoides (Mild Water-Pepper) · P. islandicum (Island Purslane) · P. lacerum (Fringed Knotweed) · P. lapathifolium (Curltop Ladysthumb) · P. lapathifolium var. lapathifolium (Curltop Ladysthumb) · P. leptocarpum (Narrow-Point Knotweed) · P. marinense (Marin Knotweed) · P. meisnerianum (Branched Tearthumb) · P. meisnerianum var. beyrichianum (Branched Tearthumb) · P. minimum (Broadleaf Knotweed) · P. mite (Tasteless Water Pepper) · P. multiflorum (Fo-Ti) · P. nepalense (Nepalese Smartweed) · P. odoratum (Vietnamese Coriander) · P. orientale (Kiss Me Over the Garden Gate) · P. orientale 'Shiro-Gane Nishiki' (Variegated Kiss Me Over The Garden Gate) · P. oxyspermum (Sharpfruit Knotweed) · P. oxyspermum raii (Sharpfruit Knotweed) · P. paronychia (Beach Knotweed) · P. paronychioides (Knotweed) · P. parryi (Parry's Knotweed) · P. patulum (Bellard's Smartweed) · P. pensylvanicum (Pennsylvania Knotweed) · P. perfoliatum (Asiatic Tear Thumb) · P. persicaria (Lady's Thumb) · P. persicaria persicaria (Lady's-Thumb) · P. phytolaccifolium (Mountain Lice) · P. polycnemoides (Manyleg Knotweed)

More Info

[ Back to top ]

Further Reading

[ Back to top ]

Notes

[ Back to top ]

Contributors

Identifiers

Footnotes

  1. Anjen Li, Bojian Bao, Alisa E. Grabovskaya-Borodina, Suk-pyo Hong, John McNeill, Sergei L. Mosyakin, Hideaki Ohba & Chong-wook Park "Polygonaceae". in Flora of China Vol. 5 Page 277. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. Mihai Costea, François J. Tardif, Harold R. Hinds "Polygonum". in Flora of North America Vol. 5. Oxford University Press. Online at EFloras.org. [back]
  3. "Polygonum hickmanii". in Flora of North America Vol. 5. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/15/2012