Stuckenia filiformis (Pers.) Börner subsp. borealis (Raf.) comb. nov.
Potamogetonaceae, pondweed family.
Potamogeton borealis Raf., Med. Repos. New York, ser. 2, 5: 354. 1808.
Potamogeton filiformis Pers. subsp. borealis (Raf.)
Hultén .
Potamogeton filiformis Pers. var. borealis
(Raf.) H.St.John, Rhodora 18: 134. 1916.
Type: Canada: St. Lawrence River, leg. A.Michaux (P) holotype.
Stuckenia filiformis (Pers.) Börner subsp. alpina sensu
R.R.Haynes, Les & M.Kral, non Blytt.
Potamogeton filiformis Pers. var. alpinus (Blytt) Aschers and
Graebn.
Potamogeton filiformis var. borealis (Raf.) St. John.
(Hultén 1968).
Potamogeton filiformis var. macounii
Morong. Hultén (1968) indicated that var. borealis has a shorter,
more compact spike of greater length than the leaves, low growth, and seems to
be merely a growth form and apparently an adaptation to Northern conditions.
Vegetative morphology. Plants perennial herbs; (5–)10–30 cm high (or more in deep, clear, "warm" water); aquatic, grass-like when the plants are not in flower; vegetatively proliferating by bulbils or fragmentation (propagules are white tubers borne at the ends of rhizomes). Taproot present. Ground-level or under-ground stems horizontal; stoloniferous, or rhizomatous (if horizontal stems become buried in soft mud); elongate, or compact. Aerial stems erect (flaccid, jointed and leafy); glabrous. Leaves distributed along the stems; alternate (all submerged); simple; existing for a single season or less. Stipules present (united at their base, separate at the attenuate tips; variable in form); scale-like (5–12 mm long); brown (pale), or green. Petioles absent. Blades 25–100(–120) mm long; 0.2–0.7 mm wide (filiform). Blades membranous; linear; veins parallel. Leaf apices acute.
Reproductive morphology. Flowering stems present. Flowering stems without leaves; glabrous. Inflorescence spicate (with 2–4 whorls of flowers). Flowers per inflorescence 6–14; small, less than 5 mm in diameter or length; actinomorphic. Calyx sepals 4; free (one single whorl of sepal-like tepals that are fleshy-firm, valvate and shortly clawed). Calyx green; fleshy; glabrous. Petals absent. Stamens 4. Gynoecia superior. Carpels apocarpous; 4 (alternating with the stamens). Styles absent. Ovules 1. Fruit with calyx persisting; dry; an achene; spherical (somewhat flattened); indehiscent. Fruit 1.8–2 mm long; 1.6–1.8 mm wide; black, or brown (where seed shows through the thin green fruit wall); glabrous. Seeds 1 (per carpel, the seed attached to the ventral margin of the carpel towards the base); 0.3–0.4 mm long; brown; with surfaces smooth (or with a slight ridge and a few tubercles).
Chromosome information. 2n = 78. 78 (6x). - Jørgensen et al. (1958 Greenland); Löve and Ritchie (1966 northern Canada); Löve and Löve (1981b northern Canada). Ploidy levels recorded 6x.
Distribution. Northern hemisphere distribution: North American (mainly). Low arctic. Range in the Canadian Arctic Archipelago limited. Uncommon. Arctic Islands: Baffin (recorded from Iqaluit), Southampton (Coral Harbour).
Ecology and habitat. Substrates: aquatic; silt. Habitats: mud in shallow lakes and pools; only the inflorescence emergent.
Notes. 'A good duck food' (Fassett 1940).
The stipules of
Stuckenia are adnate to the blade for two-thirds to nearly the entire
length of the stipule. The few species of Potamogeton with adnate
stipules have the adnation less than half the length of the stipule, or less
than 4 mm. Submerged leaves of Potamogeton are translucent, flat and
without grooves or channels, whereas those of Stuckenia are opaque,
channeled and turgid (Haynes and Haynes, 1996).
Three distinct subspecies
apparently occur in North America. They are separated mainly by the size of the
plants and peduncle characteristics.
A proposal to elevate
Potamogeton subg. Colegeton, was presented by Haynes and Haynes
(1996). Potamogeton pectinatus was chosen as the nomenclatural type. The
name Stuckenia had been previously published, however, and P.
pectinatus cited (C. Böner 1912), making the generic name
Coleogeton superfluous. Stuckenia is the correct name and the
appropriate specific combinations have been made (Holub 1997). (Haynes, D.H. and
R.R. Haynes,1996).
The Flora of North America treatment stated that no
specimens had seen seen from Nunavut, but the subspecies is to be expected there
(Haynes, D.H. and R.R. Haynes, 1996). Vouchers specimens for the three Nunavut
records on the map in the image library, are housed at CAN.
Glooschenko and
Martini (1987) in a study made of the vegetation of four river-influenced
coastal marshes located between the Moose River and Harricanaw River in southern
James Bay, found six major grouping of species. These included 1. a salt marsh
dominated by Puccinellia phryganodes, P. lucida, Hippuris
tetraphylla, and Scirpus maritimus 2. saline ponds with Senecio
congestus, 3. a saline/brackish meadow marsh with Carex paleacea, 4.
an intertidal estuarine marsh with Eleocharis palustris, 5. freshwater
ponds with Potamogeton filiformis, and 6. a freshwater marsh/fen. Major
environmental factors controlling the distribution of these groups include
substrate salinity, river flow patterns, storm surges and tidal range. These
marshes are unique in species composition in James Bay.
Haynes &
Hellquist (2000, Fl. N. Amer. 22) divided the species on three subspecies in
North America - subsp. filiformis, alpina, and occidentalis
- but their application outside North America is problematic. They consider the
'alpina' entity (described from Norway) as synonymous with the
'borealis' entity (described from North America), with priority for the
former. This synonymisation may be artificial. The 'alpina' entity is
considered by Russian and NW European botanists to be just a northern and alpine
minor race or modification of the narrow-leaved 'filiformis' whereas
'borealis' seems to be a more significant broad-leaved North American
entity. There are also possibly problems connected with the
'occidentalis' entity, see below. We therefore propose to keep
'alpina' and 'borealis' as different and to synonymise the former
with subsp. filiformis. We don't know where the limit between
'filiformis' (incl. 'alpina') and 'borealis' runs. The main
character separating Eurasian and North American plants is leaf width,
0.2–0.4 vs 0.5–0.8 mm. (Tzvelev & Elven personal communication
2002).
Illustrations. • Herbarium specimen. Plant less than 15 cm tall with small inflorescence and flowers or fruit close together. Nunavut, Baffin Island, Iqaluit, 1 km west of the airport terminal in a shallow pool, growing with Hippus. D.F. Brunton, and K.L. McIntosh 9901. CAN 549906. • Close-up of stipule. Midstem stipule with summit, indicated by the upper arrow, close to the stem and about the same width as the stem. Lower arrow, stipular sheath inflated on proximal portion of the stem. Nunavut, Baffin Island, Iqaluit, 1 km west of the airport terminal in a shallow pool, growing with Hippus. D.F. Brunton, and K.L. McIntosh 9901. CAN 549906. • Arctic Island Distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
