AN ILLUSTRATED KEY TO THE ONAGRACEAE OF ALBERTA Compiled and written by Linda Kershaw & Lorna Allen January 2020 © Linda J. Kershaw & Lorna Allen This key was compiled using information primarily from Moss (1983), Hitchcock et. al. (1955-69), Douglas et. al. (1999), Lesica 2012, and Gleason and Cronquist (1991). Taxonomy follows VASCAN (Brouillet, 2019). The main references are listed at the end of the key. Please let us know if there are ways in which the keys can be improved. The 2018 S-ranks of rare species (S1; S1S2; S2; S2S3; SH; SU, according to ACIMS, 2018) are noted in superscript (S1;S2;SU) after the species names. For more details go to the ACIMS web site. Similarly, exotic species are followed by X, XX if noxious and XXX if prohibited noxious according to the Alberta Weed Control Act (2016) in superscript (X; XX; XXX). ONAGRACEAE Evening-primrose Family Key to Genera 01a Flower parts in 2s; fruits teardrop-shaped, 1-seeded capsules, (1)2 mm long, not splitting open, covered in hooked bristles; leaves paired, egg- to heart-shaped, 2-5 cm long, usually toothed. Circaea alpina 01b Flower parts in 4s (stamens 8); fruits many- seeded capsules (rarely nut-like with 1-4 seeds), >2 mm long, mostly splitting open, not covered with hooks; leaves alternate or paired, 1a mostly linear to lance-shaped, with or without teeth. .02 2a 02a Fruits 1- to 4-seeded, not splitting open, hard, nut-like, 5-9 mm long; flowers ± bilaterally symmetric, white or scarlet. Oenothera suffrutescens . [Gaura coccinea] 02b Fruits many-seeded capsules, >9 mm long and/or not hardened, splitting open when mature; flowers mostly radially symmetric, white, pink, red, purple, or yellow ........03 03a Branches very slender and hair-like; ovaries/ capsules 2-chambered, splitting lengthwise along 4 lines when mature; Waterton area ... .Gayophytum racemosum S1 03b Branches not hair-like; ovaries/capsules 4-chambered, splitting open along 4 lines when mature ........................04 4a 04a Seeds tipped with a tuft of hairs. 05 3a 04b Seeds without a tuft of hairs ............06 4b 2 5a 05a Leaves alternate (sometimes a few pairs at the base); petals >1 cm long, rounded at the tip, pink to rose-purple (rarely white); sepals separate to the base; styles bent downwards; stigmas 4-lobed . .Chamaenerion . .[Epilobium (in part); Chamerion] 05b Leaves mostly paired or whorled (sometimes alternate on the upper stem); petals <1 cm long, notched at the tip, white, pink or rose- purple; sepals joined at the base for up to 3/4 of their length; styles not bent downwards; stigmas not 4-lobed (except E. luteum, which 5b has yellow flowers) .....Epilobium (in part) 06a Young seeds with a tuft of hair, but this soon shed; calyx lobes erect at flowering time; petals white or rose, 3-5 mm long; Dry Mixedgrass in seAB. Epilobium campestre S3 . [Boisduvalia glabella] 6a 06b Seeds hairless; calyx lobes spreading or bent back/down at flowering time; petals various 07 7a 07a Stigmas 4-lobed; in boreal, parkland and/or grassland habitats in AB. .Oenothera 07b Stigmas spherical; rare, in Dry Mixedgrass habitats in sAB. .08 08a Plants without leafy stems; leaves lance- shaped, pinnately lobed, in a basal rosette . Taraxia breviflora S1 8a .[Camissonia breviflora; Oenothera breviflora] 08b Plants with leafy stems; leaves linear to narrowly spoon-shaped, smooth-edged, 8b alternate on the stem. .Neoholmgrenia andina S1 . .[Camissonia andina, Oenothera andina] - - - - - - - - - - - - - - - - - - - - - - - CHAEMNERION Fireweed 1a 01a Plants (5)10-40(70) cm tall; leaves broadly lance-shaped to elliptic, 1-5.5(10) cm long, often slightly fleshy with a bluish coating and poorly defined veins; flower clusters short, leafy, with 1-7(15) flowers; petals 13-32 mm long; styles shorter than the stamens; seeds 1.3-2.4 mm long. .Chamaenerion latifolium . [Epilobium latifolium; . Chamerion latifolium] 01b Plants 100-300 cm tall; leaves narrowly lance-shaped (2)10-15(2) cm long, green, membranous, veiny beneath; flower clusters elongated, with small bracts and many flowers; petals 10-20 mm long; styles longer than the stamens; seeds 1-1.3 mm long. Chamaenerion angustifolium . [Epilobium angustifolium; . Chamerion angustifolium] 1b 3 EPILOBIUM Willowherb Epilobium species are often difficult to distinguish. Many hybridize freely and/or appear similar in the field; most traits can vary with environment. Microscopic seed coat characteristics are the 2a most reliable feature for identifying species. 01a Plants annual from weak taproots; stem bases with peeling (exfoliating) outer layers; usually on dry sites in sAB. 02 01a Plants perennial from well-developed roots, often spreading via stolons, rootstocks, suckers (soboles) or basal bulblets (turions); stem bases not peeling; usually on moist sites in the mountains and cAB to nAB; seeds narrowly egg-shaped, 0.3-0.8 mm wide. 03 02a Mature seeds without a tuft of hairs (young seeds tufted but hairs soon shed); capsules stalkless, 4.5-8 mm long; leaves mostly alternate, paired near the base only; seeds spindle-shaped, 1.0-1.3 x 0.4-0.6 mm . .Epilobium campestre S3 [Boisduvalia glabella; Epilobium pygmaeum] 02b Mature seeds tipped with a tuft of hairs; capsules stalked, 15-32 mm long; leaves all 2b or mostly paired, sometimes alternate on the upper stem; seeds egg-shaped, 1.5-2.7 x 0.8- 1.3 mm. .Epilobium brachycarpum . [Epilobium paniculatum] 03a Petals yellow or cream, (4)8-26 mm long; stigmas 4-lobed, usually projecting beyond the anthers; by subalpine streams. Epilobium luteum S1 03b Petals white, pink or rose-purple, 1.6-10(14) mm long; stigmas club- or head-shaped, usually surrounded by the anthers; various habitats. .04 04a Plantsgrey with dense, short, flat-lying hairs 3a (at least in flower clusters); stem leaves linear (<3 mm wide), with smooth, often down-rolled edges; plant bases with thread-like stolons ending in compact, fleshy bulblets (turions) .05 04b Plants not grey with flat-lying hairs, usually ± hairless or glandular-hairy; stem leaves either toothed and linear or smooth-edged and not 5b linear, not down-rolled; stolons absent .....06 05a Leaves linear to lance-shaped or oblong; nearly hairless on the upper surface, with 5a short, flat-lying hairs on the midrib and edges only; flower clusters often nodding in bud. Epilobium palustre 05b Leaves linear, rarely wider, uniformly grey with dense, small, stiff, flat-lying hairs above; flower clusters ± erect in bud ................... Epilobium leptophyllum . [Epilobium palustre (in part)] 4 06a Plants with small-leafed, creeping stems above- or below-ground; flowering stems ascending (rarely erect), rarely with basal scales, in clumps or mats ..............07 06a Plants usually with leafy basal rosettes or below-ground wintering buds; flowering stems erect, with dark basal scales, usually not clumped . 7a 11 07a Stem hairless, usually with a pale, bluish-white coating (above) and without raised lines of hairs; leaves ± stalkless and clasping; seeds 0.7-1.0(1.3) mm long, with dense, tiny pimples [papillae] in lengthwise rows. .Epilobium glaberrimum S1 07b Stems densely hairy to ± hairless, without a pale coating, with hairy, elevated lines extending down the stem from the leaf-bases; leaves with or without stalks, not clasping; seeds 0.7- 2.1 mm long, net-veined or pimply. 08 08a Stems 10-50 cm; leaf blades with small teeth, 1.5-6.2 x 0.7-2.9 cm; capsules 35-100 mm. .09 08b Stems 3-20(25) cm; leaf blades smooth-edged 9a or with few small teeth; (0.5)0.7-2.8 x 0.3-1.6 cm; capsules 17-40(55) mm. 10 09a Petals pink to rose-purple (rarely white); capsules 35-65 mm long, on 5-15 mm stalks; leaf stalks not winged; seeds usually pimply (sometimes net-veined) . .Epilobium hornemannii . [Epilobium alpinum (in part)] 09b Petals white (rarely red-veined or fading pink); 9b capsules 50-100 mm long on 15-45 mm stalks; leaf stalks sometimes winged; seeds net- 10a veined (sometimes barely wrinkled) ........ Epilobium lactiflorum . [Epilobium alpinum (in part)] 10a Plants with thin, leafy, creeping stems; flowering stems densely clumped or matted, nodding in bud, usually ± hairless near the base; capsules cylindrical, 1 mm wide, on 5-35(68) mm stalks; seeds 0.7-1.4 mm long, with a persistent tuft of hairs. Epilobium anagallidifolium . [Epilobium alpinum (in part)] 10b Plants with wiry, scaly, creeping stems and extended, semi-woody rootstocks; flowering stems clumped, erect, densely hairy near the base; capsules ± club-shaped, 2-3 mm wide, on 2-21 mm stalks; seeds (1.3)1.5-2.1 mm long, with an easily detached tuft of white hairs. Epilobium clavatum . [Epilobium alpinum (in part)] 10b 11a Plants ± glandless; stems 7-30 cm tall ....12 11b Plants glandular hairy (at least in flower clusters); stems (2)30-120 cm tall. .13 5 12a Mature flower/fruit stalks 5-16 mm; seeds 1.7- 2.2 mm, net-veined to low-pimply; plants with underground overwintering buds only. .Epilobium mirabile . [Epilobium glandulosum (in part)] 12b Mature flower/fruit stalks 15-38 mm; seeds 0.8-1.2 mm, pimply (papillose); plants with 12b underground overwintering buds and usually also with bulbils in the axils of lower to mid- stem leaves. Epilobium leptocarpum S2 . [Epilobium glandulosum (in part)] 13a Stems (3)10-120(190) cm tall, with leafy basal rosettes or large, underground bulblets (turions); seeds with lengthwise ridges tiny 12a bumps/pimples; leaf blades (1)3-12(16) cm long; petals 2-14 long mm, white, pink, or rose purple. Epilobium ciliatum . [Epilobium glandulosum (in part)] 13b Stems 2-55(60) cm tall, without rosettes, with compact underground bulblets or sometimes thick, dark-scaled shoots; seeds pimply or wrinkled; leaf blades 0.5-5.5(6.5) cm long; petals 1.6-5.5(7) mm long, white, fading or rarely pink.