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:

largefruit biscuitroot

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Spurry knotweed 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, branches spreading, surface usually bumpy

Leaves:

basal and on the stem, uniformly distributed, basal leaves usually falling off early, blades 3.5 – 6 cm long, 1 – 3 mm wide, linear to lance-shaped, base wedge-shaped, 1-veined, margin flat or slightly rolled; stipules fused, 8 – 12 mm long, bumpy; stalk 0.1 – 2 mm long

Inflorescence:

branched, axillary and terminal, spike-like, dense, flowers 2 – 5 per fused sheath

Flowers:

perianth 3 – 5 mm long, tepals overlapping, white or pink, petal-like; stamens 8

Fruits:

achenes enclosed in perianth, black, shiny

POLYGONUM KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Flowers solitary or in small axillary clusters; leaves jointed at the base with the stalk, small; outer tepals may be boat-shaped; fused stipules often dry and membranous, 2-lobed	2
1 Flowers in spike-like clusters; leaves not jointed at the base with the stalk, large; outer tepals may be winged or unwinged, but not boat-shaped (except in P. cilinode and P. convolvulus); fused stipules papery	9

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

3 Fruits black, smooth and shiny; tepals rounded	P. spergulariiforme
3 Fruits 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 stalks	P. douglasii ssp. douglasii
5 Flowers ascending or spreading	6

6 Fruits shiny; leaves linear to lance-shaped	P. ramosissimum
6 Fruits dull; leaves oval	7

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

8 Leaves on the branches the same size as the ones attached directly to the stem; sepals 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; sepals with white, pink or purple margins	P. aviculare

9 Stems slender and twining; leaves broad, base arrow-shaped	10
9 Stems not twining; leaves linear to lance-shaped, base not arrow-shaped	12

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

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

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

13 Fused stipules with bristles at the summit	14
13 Fused stipules without bristles	15

14 Rhizomes forking; perennials; fused stipules expanded at the top to create a rim; spikes to 2 cm thick; tepals not glandular	P. amphibium var. stipulaceum (= Persicaria amphibia)
14 Roots fibrous; fused stipules not expanded at the top; spikes slender, less than 2 cm thick; tepals 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 Leaf stalks attached near base of fused stipules; leaves and upper stems hairless to sparsely straight-hairy	P. coccineum var. coccineum (= Persicaria amphibia)
16 Leaf stalks attached midway on fused stipules; leaves and upper stems densely ashy-gray hairy	P. coccineum var. pratincola (= Persicaria amphibia)