sign in sign up
<<
Home , Potamogeton, Potamogetonaceae, Potamogeton alpinus, Potamogeton amplifolius, Potamogeton berchtoldii, Potamogeton crispus

AN ILLUSTRATED KEY TO THE OF ALBERTA

Compiled and writen by Lorna Allen & Linda Kershaw

April 2019

© Linda J. Kershaw & Lorna Allen This key was compiled using informaton primarily from Brayshaw (2000) and the Flora North America Editorial Commitee (2000). follows VASCAN (Brouillet, 2015). Please let us know if there are ways in which the key can be improved. The 2015 S-ranks of rare species (S1; S1S2; S2; SU, according to ACIMS, 2016) are not- ed in superscript (S1;S2;SU) afer the species names. For more details go to the ACIMS web site. Similarly, exotc species are followed by a superscript X, XX if noxious and XXX if prohibited noxious (X; XX; XXX) according to the Alberta Weed Control Act (2016). POTAMOGETONACEAE Pondweed Family Key to Genera 01a ± opposite, the base and stipule sheath of one in each pair arising within the sheath of the other, stipule sheaths encircling the stem, not attached to the lower part of the leaf blade; fowers either male or female; male fowers with 1 stamen ...... palustris 01b Leaves mainly alternate (some upper leaves 1a may appear ± opposite); sheaths joined or not joined to the lower part of the leaf; fowers with male and female parts; stamens 2 or 4 ...02 2a 02a Stipule sheaths (→) of underwater leaves free from the lower part of the leaf blade, or joined for <½ the length of the stipule; leaves underwater and foating or all underwater; → underwater blades semi-transparent, fat (not channeled); fower clusters on stiff stalks, usually held above the water, usually with 2b contiguous whorls of fowers. . 02b Stipule sheaths (→) of underwater leaves joined to lower leaf blade for ≥2/3 of the stipule length; leaves all underwater; blades opaque (not semi-transparent), channeled; fower → clusters on fexible stalks, not held above the water (sometimes foating), usually with well separated lower whorls of fowers

------POTAMOGETON Pondweed → 01a Stipules of underwater leaves joined to the lower part of the leaf blade, tipped with a small, pointed outgrowth (ligule; →) ...... 02 01b Stipules of underwater leaves free from the leaf blade or ≤1/5 joined to the lower blade, no obvious ligule ...... 03 1a 1b 02a Floating leaves absent; underwater leaves stiff, in 2 vertical rows (ranks) on the stem, lobed at the junction with the stipule, edged with small, sharp teeth, with 20-60 veins; fowering stalks branched ...... S1 02b Floating leaves often present, oval; underwater leaves lax, not conspicuously 2-ranked, smooth edged, without basal lobes, with ≤20 veins; fowering stalks unbranched ...... 2a ...... Potamogeton diversifolius SU 2b 03a Underwater leaves broadly linear-oblong to nearly circular, 3-58 mm wide ...... 04 03b Underwater leaves thread- or ribbon-like, 0.1- 10 mm wide ...... 10

3 04a Leaves all submerged and alike, wavy edged 4a with sharp, teeth; stems fattened; achene beak 2-3 mm long; hard over-wintering buds common ...... X 04b Leaves foating and submerged or all underwater, similar or varied, smooth edged; stems round; achene beak ≤1 mm long; over- wintering buds rare ...... 05 05a Underwater leaves stalkless, clasping the stem; foating leaves absent ...... 06 05b Underwater leaves stalked or stalkless, not clasping; foating leaves usually present 5a (sometimes absent) ...... 07 6a 06a Stems profusely branched above; leaf blades with a hood-like tip (splitting when pressed), the largest 10-20 cm long with bundles of smaller leaves in their axils; stipules persistent, conspicuous; fowering stalks 10-20(50) cm long; achene 4-8 mm long ...... 06b Stems with 0-few branches; leaf blades with 6b fat tips (not splitting when pressed), 1.6-13 cm long; stipules disintegrating into fbers; fowering stalks 2-10 cm (rarely longer); achene 3-3.5 mm long ...... 07a Floating leaf blades rounded to notched at the base, 27- to 49-veined; stem with conspicuous rusty or black spots; underwater leaf blades irregularly curled along the edges, mostly curved like a crescent, with 19-49 veins ...... S2 07b Floating leaf blades tapered to a wedge- 7a shaped base, 7- to 21-veined; stems without spots; underwater leaf blades fat-edged, mostly not curved, with 3-15 veins ...... 08 08a Underwater leaf stalks 2-13 cm long ...... S1 08b Underwater leaf stalks absent (rarely present, 8a short) ...... 09 09a Leaves reddish-green; foating leaves ±stalkless (often absent); achenes plump, short-stalked, 2.5-3.5 x (1.7)2-2.4 mm, tipped with a curved, 0.5-0.9 mm beak; stipules blunt- tipped; underwater leaf blades 7- to 9-veined ...... 09b Leaves bright (usually) to dark green; foating 9a 9b leaves usually with stalks ≥2 cm long; achenes slightly fattened, stalkless, 1.9-2.3 x 1.8-2 mm, with an erect, 0.3-0.5 mm beak; stipules sharp-pointed to blunt-tipped; underwater leaf blades 3- to 9-veined ......

4 10a Stems conspicuously fattened (nearly as wide as leaves); foating leaves absent; underwater leaves >2 mm wide, with 15-35 veins and many lengthwise fbers ...... 10a ...... Potamogeton zosteriformis 10b Stems round or moderately fattened; foating leaves present or absent; underwater leaves various, with <14 veins and no lengthwise fbers ...... 11 11a Floating leaves present (at least in some ) ...... 12 11b Floating leaves absent from all plants ....13 12a Underwater leaves lax, 1-10 mm wide, with prominent air chambers forming a broad band each side of midvein, 3- to 13- veined; stipules inconspicuous, red-brown, not fbrous; stalks of foating leaves continuous in colour, 2-12.5 cm long, foating leaf blades narrowly oblong- lance-shaped to oval, 2-8 x 0.4-2 cm, tapered 12a; to wedge-shaped base; fower clusters in leaf 14a axils ... SU(in part) 12b Underwater leaves rigid, 0.7-2.5 mm wide (resembling thick, bladeless stalks), without prominent air chambers, obscurely 3- to 5- veined; stipules conspicuous, whitish, fbrous; stalks of foating leaves lighter green at the blade, 5.5-29 cm long; foating leaf blades oval to ovate, 3.5-11 x 1.5-6 cm, notched at the base; fower clusters at stem tips...... 12b ...... 13a Nodes without paired glands ...... 14 13b Nodes (at least some) with paired glands. .15 14a present; stipules red-brown, delicate to fbrous; leaf blades red-brown to light green, 5-22 cm x 1-10 mm, 3- to 13-veined, with a broad band of air chambers on each side of midvein; fower clusters 1.5-5(16) cm long; achenes 2.5-4.5 x 2-3.6 mm, with fat wing-like keel ... Potamogeton epihydrus SU (in part) 14b Rhizomes absent; stipules greenish to brown or rarely white, not fbrous; leaf blades pale- to olive-green (rarely red-tinged), 1.3-8.2 cm x 0.3-2.3 mm, 1- to 3(5)-veined, without air chambers (rarely 1-2 rows each side of midrib); 14b fower clusters 0.3-1.1(3.7) cm long; achenes 1.4-2.3(2.7) x 1.1-2.2 mm, with a wavy wing- like keel ... (in part) 15a 15a 15a Stipules (→) fbrous, often whitish ...... 16 15b Stipules (→) not fbrous, green, brown or → → white ...... 17

5 16a Plants freely branched; stems fattened; nodal glands ≤0.7 mm; leaves delicate to rigid, 5- to 7(-9)-veined; fowers at stem tips or in leaf axils; over-wintering buds (→) with leaves in ±4 vertical rows, the outer leaves 2-3 per side, the inner leaves smaller, in a fan-shaped head at 90° to outer leaves . . 16b Plants few-branched; stems round to slightly fattened; nodal glands ≤0.3 mm; leaves rigid, 3- to 5(-7)-veined; fowers at stem tips; over- wintering buds with leaves in ±2 vertical rows, fattened, outer and inner leaves in the same plane and of similar size, the outer leaves 3-4 → per side ...... Potamogeton strictifolius 16a 17a Achenes rounded on the lower/outer side .18 17b Achenes keeled or ridged on the lower/outer side ...... 20 16b 18a Achenes 2.5-3.6 mm long, beak 0.8-1 mm; leaves soft and limp, 1-3.5 mm wide, blunt or rounded with a small, abrupt point at the tip, 3-veined (rarely more), with air chambers in 1-3 rows on each side of the midrib; fower clusters in leaf axils...... (in part) 18b Achenes 1.5-2.2 mm long, beak 0.1-0.6 mm; leaves soft to stiff, 0.2-2.5 mm wide, blunt or gradually tapered to a slender point at the tip, 1- to 3(5)-veined, with air chambers in 0-5 18a; 20b rows each side of the midrib; fower clusters in leaf axils or at stem tips ...... 19 19a Mature widest above the middle, with concave sides, usually beaked towards the inner side; fower clusters interrupted, with 1-3 19a slender to cylindrical stalks per ; leaves with air chambers in 0-2 rows on each side of the midrib; stipules fused ...... 19b Mature fruits widest at or below middle, sides rounded, beak at the centre; fower clusters continuous, >3 cylindrical stalks per plant; leaves with air chambers in 1-5 rows on each side of the midrib; stipules separate ...... 19b [Potamogeton pusillus ssp. tenuissimus] 20a Achenes 1.4-2.3(2.7) mm, with a conspicuous, wing-like, wavy keel and 0.2-0.6 mm beak; leaves linear, <2.3 mm wide, sharply pointed (rarely bristle-tipped), 1-3(5)-veined; stipules greenish to brown (rarely white); leaf-node glands black to gold, ≈0.5 mm (rarely present); over-wintering buds rare; fower spikes 1.5-7 mm long ...Potamogeton foliosus (in part) 20b Achenes 2.5-3.6 mm, rounded or obscurely 20a keeled, with a 0.8-1 mm beak; leaves soft and limp, linear, (1)2-3.5 mm wide, blunt or with a short, abrupt point, 3-veined (rarely more); stipules white; leaf-node glands yellow- green to gold, 0.2-1 mm; over-wintering buds abundant; fower spikes 8-13 mm long ...... Potamogeton obtusifolius (in part)

6 STUCKENIA Slender-pondweed 01a Leaf tips sharp- to short-pointed; lowest stipule sheaths not infated; stems abundantly 1b branched, especially in upper portions; achenes distinctly beaked...... 1a 01b Leaf tips blunt to notched (rarely pointed); lowest stipule sheaths often infated; stems sparsely branched in upper portions; achenes not beaked ...... 02 02a Stipules tipped with tapered outgrowths (ligules) 2-20 mm long (especially in the upper parts of the plant); tips of mid-stem stipules tight to stem, ≈ the width as the stem; achenes 2a 2-3 mm long ...... Stuckenia fliformis 02b Stipules tipped with ligules 0-2 mm long; tips of mid-stem stipules infated, 3-5 times as wide as the stem; achenes 3-3.8 mm long ...... 2b ......

7 References

Alberta Conservaton Informaton Management System (ACIMS). 2015. List of all Taxa Confrmed for Alberta as recorded in the ACIMS database - October 15 2015. ACIMS, Government of Albert, Edmonton, Alberta.

Brayshaw, C.T., 2000. Pondweeds, Bur-reeds and their Relatves of Britsh Columbia. Aquatc Families of . Royal Britsh Columbia Museum, Victoria BC.

Brouillet, L., F. Coursol, S.J. Meades, M. Favreau, M. Anions, P. Bélisle & P. Desmet. 2015. VASCAN, the Database of Vascular Plants of Canada. htp://data. canadensys.net/vascan/

Flora of North America Editorial Commitee. 2000. Flora of North America, Volume 22 Magnoliophyta: Alismatdae Arecidae, Com- melinidae (in Part), and Zingiberidae. Oxford University Press, New York.

Flora North America Editorial Commitee. 2008-10. Flora North America website. Oxford University Press. Accessed, 2014-2016. www.fna.org.

Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1955-69. Vascular plants of the Pacifc Northwest. Volume 5. University of Washington Press, Seatle, Washington.

Moss, E.H. 1983. The Flora of Alberta. Second Editon, Revised by John G. Packer. University of Toronto Press, Toronto, Ontario.

Province of Alberta. 2016. Weed Control Act, Ofce Consolidaton. Alberta Regula- ton 19/2010 with amendments up to and including Alberta Regulaton 125/2016. Alberta Queen’s Printer, Edmonton, AB.

8 List of Species and Illustration Sources Index Potamogeton 3 Scientfc Name Illus. Source alpinus 4 Potamogeton alpinus H&C amplifolius 4 Potamogeton amplifolius H&C berchtoldii 6 Potamogeton crispus H&C crispus 4 Potamogeton diversifolius H&C diversifolius 3 epihydrus 5 Potamogeton epihydrus H&C foliosus 5, 6 Potamogeton foliosus H&C friesii 6 Potamogeton friesii H&C; LK gramineus 4 Potamogeton gramineus H&C natans 5 Potamogeton natans H&C nodosus 4 Potamogeton nodosus H&C obtusifolius 6 praelongus 4 Potamogeton obtusifolius B&B pusillus 6 Potamogeton praelongus H&C ssp. tenuissimus. See Potamoge- Potamogeton pusillus H&C ton berchtoldi Potamogeton richardsonii H&C richardsonii 4 Potamogeton robbinsii H&C robbinsii 3 strictifolius 6 Potamogeton strictfolius LK zosteriformis 5 Potamogeton zosteriformis H&C Potamogetonaceae 3 Stuckenia fliformis H&C Stuckenia 3, 7 Stuckenia pectnata H&C fliformis 7 Stuckenia vaginata H&C pectinata 7 H&C vaginata 7 Zannichellia palustris 3

Key to Illustration Sources

B&B = Britton, N. L. and A. Brown (1913)

H&C = Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson (1955-69)

LK = Linda Kershaw.

9