Isoetes muricata var. hesperia Reed:
United States (North America)

Isoetes echinospora subsp. muricata (Durieu) Á. Löve & D. Löve:
United States (North America)

Isoetes echinospora Durieu:
Canada (North America)
France (Europe)
United States (North America)

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

North American plants of Isoëtes echinospora, which bear stomata, have been called I. muricata or I. echinospora var. braunii to distinguish them from European plants of I. echinospora, which do not have stomata.  

Isoëtes echinospora is a distinct species but has considerable variation, especially in size, color, and form of leaves. It is the most commonly encountered quillwort in oligotrophic, noncalcareous lakes and ponds of northeastern North America.  

Isoëtes echinospora hybridizes with I. bolanderi; I. engelmannii [ = I. x eatonii Dodge (later synonym = I. x gravesii A. A. Eaton)]; I. lacustris [ = I. x hickeyi Taylor & Luebke]; I. maritima; I. riparia [ = I. x dodgei A. A. Eaton]; and I. tuckermanii.

Plants usually aquatic, occasionally emergent. Rootstock nearly globose, 2-lobed. Leaves ± deciduous, bright green to reddish green, pale toward base, spirally arranged, to 25(--40) cm, pliant, gradually tapering toward tip. Velum covering less than 1/2 of sporangium. Sporangium wall ± brown-streaked. Megaspores white, 400--550 μm diam., echinate with thin, sharp spines; girdle obscure. Microspores gray to light brown in mass, 20--30 μm, smooth to spinulose. 2n = 22.

Isoëtes braunii Durieu; I. echinospospora subsp. muricata (Durieu) A. Löve & D. Löve; I. echinospora var. boottii Engelmann; I. echinospora var. braunii (Durieu) Engelmann; I. echinospora var. muricata (Durieu) Engelmann; I. muricata Durieu; Isoëtes setacea Lamarck subsp. muricata (Durieu) Holub

Type collection for Isoetes echinospora var. robusta Engelm.
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): C. G. Pringle
Year Collected: 1879
Locality: Vermont, United States, North America

Spores mature in late summer. Emergent or in shallow, cool, oligotrophic water of slightly acidic lakes, ponds, and streams; Greenland; Alta., B.C. Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Calif., Colo., Conn., Idaho, Maine, Mass., Mich., Minn., Mont., N.H., N.J., N.Y., Ohio, Oreg., Pa., R.I., Utah, Vt., Wash., Wis.; circumboreal.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Species: 1
Species With Barcodes: 1

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: G5 - Secure

Comments: Sometimes treated as Isoetes setacea ssp. muricata (e.g., Weber, checklist Colorado), as I. muricata, or as I. echinospora ssp. muricata; these all considered here to be equivalent to the usage of I. echinospora by Kartesz (1994). LEM 12Apr95.