Species: Polygonum spergulariiforme Meisn. ex Small

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Polygonum spergulariiforme Meisn. ex Small

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TAXONOMY

Family:

Polygonaceae

Genus:

Polygonum

Species Synonyms:

Polygonum douglasii spp. spergulariiforme (Meisn. ex. Small) Hickman.

Common Names:

spurry knotweed

DISTRIBUTION

Canada:

southern British Columbia, southwestern Saskatchewan

Saskatchewan:

southwestern Saskatchewan; Altawan

Ecoregion:

Mixed Grassland

HABITAT

Saskatchewan:

dry to moist soils

Associated Species:

Lomatium macrocarpum

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Polygonum spergulariiforme is endangered because of extreme rarity in Saskatchewan. It is regionally restricted to the southwest corner of the province. No immediate threats are known but may occur in the future.

SPECIES DESCRIPTION

Height:

5 – 50 cm

Stems:

erect, slender, green, divaricately branched, usually papillose

Leaves:

basal and cauline, uniformly distributed, basal leaves usually caducous, blades 3.5 – 6 cm long, 1 – 3 mm wide, linear to lanceolate, base cuneate, 1-veined, margin flat or slightly revolute; ocrea 8 – 12 mm long, papillose; petiole 0.1 – 2 mm long

Inflorescence:

cymes axillary and terminal, spicate, dense, flowers 2 – 5 per ocreole

Flowers:

perianth 3 – 5 mm long, tepals overlapping, white or pink, petaloid; stamens 8

Fruits:

achenes enclosed in perianth, black, shiny

POLYGONUM KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Flowers solitary or in small axillary clusters or open racemes; leaves jointed at the base with the petiole, small; outer tepals may be keeled; ocrea often hyaline, 2-lobed	2
1 Flowers in spicate racemes; leaves not jointed at the base with the petiole, large; outer tepals may be winged or unwinged, but not keeled (except in P. cilinode and P. convolvulus); ocrea chartaceous	9

2 Inflorescence compact	3
2 Inflorescence a slender, open raceme	5

3 Achenes black, smooth and shiny; tepals rounded	P. spergulariiforme
3 Achenes yellowish to dark brown, not shiny; tepals pointed	4

4 Bracts definitely white-margined; stems to 20 cm tall	P. polygaloides var. confertiflorum
4 Bracts only slightly white-margined, if at all; stems less than 20 cm	P. polygaloides var. kelloggii

5 Flowers on reflexed pedicels	P. douglasii ssp. douglasii
5 Flowers ascending or spreading	6

6 Achenes shiny; leaves linear to lanceolate	P. ramosissimum
6 Achenes dull; leaves oval	7

7 Perianth bottle-shaped, outer tepal hooded	P. achoreum
7 Perianth not constricted below the apex, outer tepal not hooded	8

8 Leaves on the branches the same size as the ones attached directly to the stem; calyx with greenish-white or pink margins	P. arenastrum (= P. aviculare ssp. depressum)
8 Leaves on the branches much smaller than the ones attached directly to the stem; calyx with white, pink or purple margins	P. aviculare

9 Stems slender and twining; leaves broad, base hastate	10
9 Stems not twining; leaves linear to lanceolate, base not hastate	12

10 Ocrea with a ring of bristles	P. cilinode (= Fallopia cilinodes)
10 Ocrea lacking bristles	11

11 Fruiting calyx to 5 mm long, wings small; plants annual	P. convolvulus var. convolvulus (= Fallopia convolvulus)
11 Fruiting calyx to 1.5 cm long, wings broad; plants perennial	P. scandens var. scandens (= Fallopia scandens)

12 Leaves mainly basal, cauline leaves few and reduced	P. viviparum (= Bistorta vivipara)
12 Leaves mainly cauline, well-developed	13

13 Ocrea with bristles at the summit	14
13 Ocrea without bristles	15

14 Rhizomes forking; perennials; ocrea expanded at the top to create a flange; spikes to 2 cm thick; perianth not glandular	P. amphibium var. stipulaceum (= Persicaria amphibia)
14 Roots fibrous; ocrea not expanded at the top; spikes slender, less than 2 cm thick; perianth glandular	P. punctatum var. confertiflorum (= Persicaria punctata)

15 Annuals, terrestrial; roots fibrous; spikes terminal and axillary, numerous	P. lapathifolium var. lapathifolium (= Persicaria lapathifolia)
15 Perennials, often aquatic; rhizomes forking; spikes terminal, solitary or paired	16

16 Petioles attached near base of ocrea; leaves and upper stems glabrous to sparsely strigose	P. coccineum var. coccineum (= Persicaria amphibia)
16 Petioles attached midway on ocrea; leaves and upper stems densely ashy-gray pubescent	P. coccineum var. pratincola (= Persicaria amphibia)