Eriophorum vaginatum L. var. spissum (Fernald) B. Boivin Eriophorum spissum Fernald Eriophorum spissum Fernald var. erubescens (Fernald) Fernald Eriophorum vaginatum L. ssp. spissum (Fernald) Hultén Cotton sedge, hare’s-tail cottongrass, tussock cottongrass, sheathed cottonsedge
Hare’s-tail cottongrass is a tussock-forming sedge native to North America, with a preference for peaty bogs and acidic wetlands. Plants: Stems (culms) are round, oval, or triangular in cross section. The stems are very thin, about ¹/₃₂" (), and densely packed into tussocks. Leaves: There are a few basal, alternate leaves, and a few higher up, but they are easy to miss amongst the many stems. Each leaf is up to ¹/₃₂" (1 mm) wide, resembling a grass blade, and may be nearly as long as the stem. Flowers: Flowers appear in a compact cluster at the tip of the stem, appearing elliptic at first, then more hemispheric as the plant matures. If you look closely, the numerous flowerheads are arranged in a spiral pattern. The cottony flowerheads are ¾-2" (1.9-5 cm) in size. Fruits: ¹/₁₆-⅛" (1.9-3.5 mm) long. They are triangular to rounded in cross-section. White bristles around the base of each flower extend in length, becoming ¼-¾" (8.3-19 mm) long, producing the “cotton.” Seeds (achenes) are ¹/₁₆-⅛" (1.9-3.5 mm) long, and shaped like teardrops. They are three-sided when viewed in cross section. The tussocks of narrow stems, white bristles (vs. brownish), and erect (vs. nodding) orientation are identifying features. These are closely similar: |
7/13/2015 · Mt. Mansfield, Stowe/Cambridge, Vermont 7/13/2015 · Mt. Mansfield, Stowe/Cambridge, Vermont 7/13/2015 · Mt. Mansfield, Stowe/Cambridge, Vermont |
|||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||
You are here Eriophorum vaginatum var. spissum |
Eriophorum virginicum |
Rhynchospora alba |
||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Common Name | ![]() |
![]() |
![]() |
|||||||||||||||||||||||||||||
Plant | Stems (culms) are round, oval, or triangular in cross section. The stems are very thin, about ¹/₃₂" (), and densely packed into tussocks. | Stems are not branched, hairless, and 16-48" (40-121 cm) in height. They are single, or in small groups, with round or slightly triangular cross sections. | Stems are up to 20" (50 cm) in height, round or oval to weakly triangular (“obscurely triangular,” according to one source) in cross-section. They are not branched and hairless, and are cespitose: often occuring in clumps. | |||||||||||||||||||||||||||||
Flowers | Flowers appear in a compact cluster at the tip of the stem, appearing elliptic at first, then more hemispheric as the plant matures. If you look closely, the numerous flowerheads are arranged in a spiral pattern. The cottony flowerheads are ¾-2" (1.9-5 cm) in size, erect (vs. nodding) and are white (vs. brownish). | Although they often look like a single tuft of cotton, the tuft is comprised of 2-10 densely packed spikelet clusters. The lowermost spikelets are wrapped in leafy bracts, like tiny ears of corn. Each spikelet is ⅛-⅜" (6-10 mm) long. Ten or more threadlike bristles—the “cotton”—extend from the base of each flower. The threads eventually become up to ¾" (2 cm) long, usually brown at the base, and somewhere between off white and brown or red-brown as the plant ages. The red-brown color distinguishes tawny cotton-grass from other cotton grasses. (More subtle identifiers include a single stamen per floret instead of 3, and multiple veins on the scales of the seedheads.) Flowers appear from Jun to Sep. | White, rounded clusters of spikelets turn light brown with age. Usually there is a single cluster, but there may be one or two additional clusters. Clusters are ⅜-⅞" (1-2.5 cm) in size, comprised of spikelets that are ⅛-³/₁₆" (3.5-5.5 mm) long, and narrowly elliptic: shaped like miniature ears of corn. | |||||||||||||||||||||||||||||
Leaves | There are a few basal, alternate leaves, and a few higher up, but they are easy to miss amongst the many stems. Each leaf is up to ¹/₃₂" (1 mm) wide, resembling a grass blade, and may be nearly as long as the stem. | Alternate, up to 12" (30 cm) long × ¹/₃₂-⅛" (1.5-4 mm) wide. They are linear, flat at the base, becoming triangular in cross section as they approach the tip, with parallel veins. They may be erect, or floppy. | Grasslike leaves are flat at the base, becoming triangular in cross-section toward the end, ~¹/₃₂" (~) in width. Sheaths enclosing blades around the culm are closed. | |||||||||||||||||||||||||||||
Fruit | ¹/₁₆-⅛" (1.9-3.5 mm) long. They are triangular to rounded in cross-section. White bristles around the base of each flower extend in length, becoming ¼-¾" (8.3-19 mm) long, producing the “cotton.” Seeds (achenes) are ¹/₁₆-⅛" (1.9-3.5 mm) long, and shaped like teardrops. They are three-sided when viewed in cross section. | Fruits appear from July to September. The achenes are ¹/₁₆-⅛" (2.5-4 mm) long, shaped like a narrow ellipse with a triangular or rounded cross section. They are brown or black. | Achenes are lenticular (“lens-shaped”), ~¹/₃₂" (~) wide, narrowing to a stalk at the base. Each spikelet contains one or two achenes. Mature spikelets are brown. A tangle of 9 to 12 bristles surround the base of each spikelet. | |||||||||||||||||||||||||||||
Range/ Zones |
|
|
|
|||||||||||||||||||||||||||||
Habitats | Peaty bogs and acidic wetlands. | Wet, peaty, acidic soil, such as bogs, damp meadows, and conifer swamps. | Bogs, peatlands, floating mats. | |||||||||||||||||||||||||||||
Type | Wild | Wild | Wild |
Online References:
Eriophorum vaginatum var. spissum at Minnesota Wildflowers
Eriophorum vaginatum var. spissum on Wikipedia
Eriophorum vaginatum var. spissum on gobotany.nativeplanttrust.org
Eriophorum vaginatum var. spissum on plantfinder.nativeplanttrust.org
References:
Eriophorum vaginatum var. spissum description by Thomas H. Kent, last updated 16 Sep 2020.
© FloraFinder.org. All rights reserved.
Range: