Carex bigelowii Torr. in Schwein. subsp. bigelowii
Cyperaceae, sedge family.
In Ann. Lyc. N. Y. 1: 67. 1824.
Nomenclatural section used by Flora of North America project subgenus Carex, sect. Phacocystis Dumortier
Carex bigelowii subsp. hyperborea (Drejer) Böcher
Carex anguillata Drejer
Carex bigelowii forma
anguillata (Drejer) Fernald
Type: Described from USA: New Hampshire, White Hills, type in PH.
Vegetative morphology. Plants perennial herbs; 3–20(–30) cm high; coarse, stoloniferous, with stout, scaly ground-level stems. Culms, stiff, smooth and sharply triangular. Roots pallid-brown. Ground-level or under-ground stems horizontal; rhizomatous, or stoloniferous; elongate. Scales present. Aerial stems erect; triangular in cross-section; glabrous. Leaves in a basal tuft. Petioles absent. Sheaths persisting (first year), or breaking down into fibres (with age); not forming a conspicuous build up at the base of the plant; greyish brown, or brown; collars absent. Ligules present. Blades (40–)80–160(–200) mm long; 0.5–2.5 mm wide. Blades straight; linear; flat, or revolute; veins parallel; not septate nodulose (distinguishes this species from C. aquatilis). Blades adaxial surface glabrous (strongly ribbed). Blades abaxial surface glabrous. Blade margins scabrous (scaberulous at the tip).
Reproductive morphology. Plants monoecious. Flowering stems present. Flowering stems conspicuously taller than the leaves; with leaves; glabrous. Leaf or reduced bract closely associated with the base of the inflorescence present; conspicuous and leaf-like; similar in length to the inflorescence, or shorter than the apex of the inflorescence; 25–35 mm long; sheathless (the base of the blade may enclose the stem at the node, but there is no sheath covering any part of the internode); persistent. Inflorescence spicate; (1.5–)3–6(–8) cm long; (5–)10–15 mm wide. Pedicels glabrous. Inflorescence multispicate; 2–3(–4) spikes; lateral spikes borne on pedicels (usually pistillate, but occasionally with a few staminate flowers). Individual spike(s) ascending. Terminal spike wholly staminate (usually). Cladoprophyll present at the base of the peduncle of lateral spikes. Staminate flowers conspicuous. Floral scales shorter than the perigynium in fruit (green sides of the perigynia visible around the edges of the darker scales); black; with margins darker in colour than the midvein (mid-vein light brown or green); obtuse; 2.5–3.5 mm long; 1.2–2 mm wide; glabrous. Perianth absent. Flowers unisexual. Stamens 3. Anthers 3.3–3.7 mm long. Carpels syncarpous. Styles slender, not extending beyond the beak. Stigmas per style 2. Placentation basal. Fruit surrounded by a perigynium. Perigynia fused to the apex except for a small aperture through which the style protrudes; broadly ovate; 2.3–3 mm long; 1.3–1.7 mm wide; contracted at the base into a stipe-like structure (0.15–0.45 mm long); erect or ascending; green (often with purple spots at the apex); membranous; surface dull; glabrous; papillose; appearing nerveless; with 2 keels; apices merely conical or rounded. Fruit an achene. Achenes filling the perigynia; lenticular.
Chromosome information. 2n = 68 and 70 (Faulkner, 1972). 70. - Löve and Löve (1966b north eastern USA); Löve and Löve (1981c northern Canada).
Distribution. Northern hemisphere distribution: amphi-Beringian; Greenland, Canada, United States. Northwest Territories Islands (?), Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. Arctic. Range in the Canadian Arctic Archipelago widespread. Common. Arctic Islands: Baffin, Devon, Ellesmere, Southampton, and Banks (literature record; possibly a misidentification of subsp. lugens).
Ecology and habitat. Substrates: hummocks (mossy), along streams, tundra (often windswept), slopes, ridges (also raised sandy beaches), cliffs; dry, or imperfectly drained moist areas (less commonly); rocks, gravel, sand; with low organic content. Habitats: Typically found in high, dry ledges and ridges; also in sandy areas between boulders. Common associates in this habitat are Empetrum and Arctostaphylos. Carex bigelowii also occurs in meadows with other Carex and with Eriophorum. Somewhat less commonly found in moist tundra and along streams.
Notes. Polunin (1940) considered this a widespread and very variable
species indicating that it may be strongly stoloniferous and 10–40 cm high
or closely tufted and only 4–5 cm high. There is a form with narrow
perigynia and long and stiff peduncles to the lower spikes which is sometimes
separated as C. anguillata. Polunin (1940) concluded it was best to
include this and all other forms in the eastern Arctic under the same name and
this has generally been done. McLaren (1964) indicated that C. anguillata
was an addition to the flora of the Arctic Archipelago. Two specimens that he
collected on Baffin Island at Ogac Lake are at CAN. They are relatively delicate
plants but within the concept of C. bigelowii. Another specimen, CAN
204794, collected from the head of Clyde Inlet, Baffin Island, was annotated by
Porsild (1958) as ?C. anguillata (Drejer) Fern; "a peculiar form in which
the terminal spikes are female at most with 1–2 male flowers near the
summit". These document considerable variation in C. bigelowii as treated
here. Polunin (1940) discussed why the names C. concor R. Br. and C.
rigida Good cannot be used.
In moist areas, the plants become taller and
occasionally have longer and more lax-flowered pistillate spikes (Porsild and
Cody, 1980).
Chater (1980) noted that this is an extremely variable species
whose infraspecific taxonomy is confused by its apparent similarity to small
variants of Carex aquatilis in the arctic, by the occurrence of numerous
hybrids, and by the fact that published work on it has never taken full account
of the variation over the full range.
Carex bigelowii is self
compatible, but protandry limits pollination within flowering shoots (Jonsson et
al., 1996). A study of genetic diversity using allozyme electrophoresis revealed
extensive genetic diversity, and indicates high levels of outbreeding in the
past. Today, the species produces many seeds and has a large, long-lived seed
bank; yet very little seedling recruitment has been observed. In Iceland
seedling recruitment has been observed only in disturbed sites. Reproduction is
mainly by clonal growth (also observed in Swedish Lapland by Wikberg et al.,
1994). The long internodes of the rhizomes break down over time resulting in a
large number of independent fragments with the same genetic composition (Jonsson
et al., 1996)
Demographic aspects in populations of the species were studied
in Swedish Lapland by Wikberg et al. (1994) at three altitudes. Tiller densities
from the highest altitudes increased significantly during the study period
(10–20 years) while those from intermediate and lower altitudes stayed
constant.
Experimental control of flowering was investigated by Heide
(1992).
In a study of scale-dependent correlation's of Arctic vegetation and
snow cover in south-eastern Victoria Island, Schaefer and Messier (1995) found
that C. bigelowii exhibited positive associations with various measures
of snow cover. It is thought that snow cover may reduce the rate of desiccation,
protect plants from abrasion, and insulate from low temperatures.
The impact
of anticipated climate changes on the population growth and vegetative spread of
Carex bigelowii was investigated by Carlsson and Callaghan (1994). They
show that increases in nutrients, carbon dioxide and temperature (expected
consequences of climate change in the Arctic) will lead to increased growth of
the species, and that young "guerrilla" type tillers will contribute
significantly to vegetative spread.
Egorova in Elven et al. (2002) proposed
merging a large part of the variation of the nearly circumpolar C.
bigelowii s. lat. into three arctic subspecies: subsp. bigelowii
(incl. C. rigida and C. hyperborea), subsp. arctisibirica
and subsp. rigidioides. This implies that also the mainly Siberian C.
ensifolia (Gorodkov) Holub s. lat. is united with C. bigelowii.
However, in the North Atlantic area there are reasons to divide Egorova's
amphi-Atlantic subsp. bigelowii (s. lat.) into aNorth
Americaerican--Greenlandic and a Greenlandic--European race. Chater in Tutin et
al. (1980), Flora Europaea 5: 320–321, separated the NW European material
on two subspecies - subsp. bigelowii (with C. hyperborea Drejer as
a synonym) and subsp. rigida W.Schultze-Motel. The former corresponds
with the tall-grown plants in S Greenland and continental NE America (but not
very well with those in the north eastern Canadian arctic islands); the latter
includes the central European and Scottish plants and also corresponds best with
the alpine Fennoscandian and Icelandic plants that reach the Arctic in Europe,
and with at least the NE Greenland plants.
Chater's treatment is based on
Schultze-Motel (1968), Willdenowia 4: 325–328. He was of the opinion that
also subsp. bigelowii occurred in Fennoscandia and as more frequent
("häufiger") here than subsp. rigida. The Scandinavian material has
not been revised according to this view, mainly because it does not fit. We have
never accepted a division of the Fennoscandian material on two subspecies as we
did not find a consistent pattern as described by Schultze-Motel.
In the
same year, Holub (1968), Folia Geobot. Phytotax. 3: 183–192, published the
combination C. bigelowii subsp. nardeticola Holub to encompass the
alpine plants in central Europe, Scotland (C. rigida sensu Gooden. 1794),
Fennoscandia, the Faeroes, Iceland, and parts of Greenland. This is a much more
acceptable division for Scandinavians than the one applied by Schultze-Motel and
Chater and fits the morphological facts. It was also accepted by Böcher et
al. (1978) for Greenland. Holub's publication came later than Schultze-Motel's
and the latter's combination has priority. As it is based on Goodenough's
Scottish C. rigida, i.e., European mountain plants, it does not matter
much as his subsp. rigida and Holub's subsp. nardeticola most
probably refer to the same taxon.
As indicated, the Greenland/American
material seems to fall into two entities, a northern and a southern indicated,
respectivelly, by the 'bigelowii' and 'hyperborea' names applied
in Greenland by Böcher et al. (1957). At that time, Böcher's
'bigelowii' probably referred to the European concept of subsp.
rigida and his 'hyperborea' to subsp. bigelowii. Later,
Böcher (1978) and Löve and Löve (1975) accepted subsp.
nardeticola as name for the northern entity which means that it was
considered as belonging to subsp. rigida in Schultze-Motel's
nomenclature.
Thus, there are two mainly allopatric entities in the North
Atlantic area (excluding Svalbard): one comparatively low-grown in northern
European mountains including Fennoscandia, Iceland, Jan Mayen and N-C Greenland
(subsp. rigida, synonym: subsp. nardeticola), and a tall-grown in
NE North America and S-C Greenland (subsp. bigelowii, synonym: C.
hyperborea).
Illustrations. • Plant habitat. Plants about 10 cm growing in dry gravel near the runway at Mt. Joy. Nunavut, Baffin Island,Soper River Valley. Aiken and Isles 02–042. CAN. Scale bar in cm. • Close-up of inflorescence. Flowering stem with leaf subtending the inflorescence that is shorter than the inflorescence, terminal spike male with brown post-anthesis anthers, and lower spike female with post-receptive stigmas. Aiken and Isles 02–042. CAN. • Close-up of plants. Loosely tufted plant. Leaf associated with the inflorescence equal to or shorter than it. Scale bar in cm. Nunavut, Baffin Island, Iqaluit. Aiken 97–002, CAN. • Close-up of inflorescence. Inflorescence with a terminal male spike and two female spikes. Green sides of the perigynia visible around the darker scales. Nunavut, Baffin Island, Iqaluit. Aiken 97–025, CAN. • Female spikes with stigmas exposed.. Inflorescence with uppermost male spike with dehisced anthers and lower tw female spikes with receptive stigmas exposed. Aiken 02–042. CAN. • Close-up of inflorescence. Male terminal spike, post-anthesis. Lower female spike has scales shorter than the perigynia. Nunavut, Baffin Island, Iquluit. Aiken, 97–025, CAN. • Close-up of inflorescence. Inflorescence with bract leaf shorter that the inflorescence, terminal male spike and lower female spike. Nunavut, Baffinin Island, Soper River Valley. Aiken 02–042. CAN. • 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).
