Kalmiopsis fragrans

Perennial, evergreen, multi-stemmed shrub that may be erect or trailing/matted. Stems have peeling reddish-gray bark. Leaves are oval to egg-shaped, dark green and shiny with golden crystalline glands on their undersides. There are 4-7 flowers per stem; flowers are reddish-purple to bright pink, fragrant, relatively large (16-28 mm), urn or bell-shaped (lacking a defined throat) to nearly flat as the petal lobes bend back. 10 stamens protrude conspicuously from each fully-open flower and have dense yellow hairs at their bases. Fruits are dry capsules that split open to release many tiny seeds. Flowers April to June and disperses seeds later in the summer (Amsberry et al. 2007, Oregon Flora Project 2007).

Kalmiopsis fragrans differs most apparently from K. leachiana in its flowers (Meinke and Kaye 2007). In this respect, K. fragrans can be distinguished from K. leachiana by its (1) glandular-hairy flower pedicels (vs. flower pedicels not glandular-hairy), (2) larger corolla (16-28(-33) mm across vs. (12-)14-20 mm across), (3) petal sinuses deeply cleft, to within 2-3 mm of the floral tube (vs. moderately cleft, to within 4-7 mm of the floral tube), (4) corolla with a poorly-defined tube, becoming nearly flat and rotate as petal lobes reflex (vs. corolla with a more well-defined tube, petals reflexing but floral tubes remaining tubular-campanulate), (5) longer stamens (7-13 mm in long-styled morph vs. 3-7(-9) mm in long-styled morph), (6) larger anthers (1.2-3.0 mm long vs. 0.7-1.8 mm long), (7) flowers with yellowish cilia densely tufted at base of filaments surrounding ovary, evident in floral tube (tube area rarely subglabrous) (vs. flowers completely glabrous, or occasionally with fine cilia lining basal interior of floral tube, but not tufted or attached to filaments), and (8) flowers with spicy-sweet azalea-like scent, with nectar merely a trace or typically absent (vs. flowers lacking a pronounced odor, with nectar pooling in floral tube). K. fragrans also differs prominently from K. leachiana in its (9) erect to trailing or matted habit (vs. usually erect habit) and (10) stem length to 12 dm and rarely up to 30 dm (vs. 2-4 dm, rarely up to 8 dm). Less conspicuously, K. fragrans can be distinguished from K. leachiana by its (10) inflorescences usually with 4-8 flowers, sometimes as few as 2 or as many as 12 (vs. inflorescences usually with 7-12 flowers, sometimes as few as 5 or as many as 15), (11) petals sculpted with ridges connected within petals (vs. ridges connected between petals), (12) light pink or reddish-purple corolla (vs. rose to deep pink corolla), (13) style 11-15 mm long in long-styled morph (vs. style 7-10 mm long in long-styled morph), (14) anthers narrowly oblong or curved linear, the pore ± round, < 0.4 mm (vs. anthers oblong, the pore flared, 0.5-0.9 mm), (15) ovary pale yellow to gold (vs. greenish gold), and (16) clearly protogynous breeding system, with pollen shed from a few hours to a day after corolla expansion (vs. slightly protandrous to slightly protogynous breeding system, with pollen shed about the time of corolla expansion). The species also differ in habitat and geographic distribution (Meinke and Kaye 2007, Oregon Flora Project 2007, Flora of North America Editorial Committee 2009). Populations typically flower from mid-April to early June, depending on elevation. Seed production and dispersal occurs into August.

Kalmiopsis fragrans usually grows on or closely adjacent to rock outcrops, steep rocky talus slopes, boulder piles, or large pillars from 400-1325 m; it can grow on nearly bare rock, in crevices, or on shallow soil. The rock type at occupied sites tends to be silicified tuff, an altered andesite substrate with a poorly developed soil layer. Sites often have south-facing aspects and can be deeply shaded to partially open. These rocky sites are found within cool, mesic mixed conifer forests dominated by Pseudotsuga menziesii, Pinus lambertiana, Abies grandis, Tsuga heterophylla, Calocedrus decurrens, and/or Thuja plicata, and often including some Arbutus menziesii. Understory associates include Mahonia nervosa, Holodiscus discolor, Gaultheria shallon, Oxalis oregana, Whipplea modesta, Chrysolepis chrysophylla, Polystichum munitum, Linnaea borealis, Rosa gymnocarpa, Pterospora andromedea, Pleuricospora fimbriolata, Allotropa virgata, Rhododendron macrophyllum, Acer circinatum, Toxicodendron diversilobum, Goodyera oblongifolia, Thermopsis montana, Iris chrysophylla, Pyrola picta, Sanicula graveolens, Viola orbiculata, Calypso bulbosa, Erythronium citrinum, and Luzula campestris (NatureServe 2024, OSU 2024).

Flowering tends to occur most profusely in sites with consistent, filtered light. Populations also occur within more densely shaded conditions (e.g., within shallow caves or overhangs while growing from high rock ceilings or along deeply sheltered cliffs); these populations can persist for years, but seldom if ever produce flowers or seed. Habitat disturbance that results in reduced soil moisture and increased sunlight (e.g., clear cutting) has been observed to cause population decline, including increased anthocyanic pigmentation, greater disease susceptibility, and higher mortality; these effects are most pronounced in populations from deeper forests (Meinke and Kaye 2007).

Kalmiopsis fragrans flowers are distylous - i.e., each plant has one of two different reproductive morphologies: longer styles/shorter stamens or longer stamens/shorter styles. In other plants, such morphologies are believed to have evolved to ensure a high rate of outcrossing; however, whether this is true for K. fragrans is still somewhat unclear (Meinke and Kaye 2007). Beyond K. fragrans and K. leachiana, distyly is otherwise unknown in the Ericaceae. Kalmiopsis fragrans floral morphology is not typical of heterostylous species (which tend to have strongly tubular, campanulate, or funnelform corollas), and the degree to which it possesses other primary traits that define heterostyly (e.g., diallelic self-incompatibility) requires further evaluation (Meinke and Kaye 2007). Field observations of pollinators indicate that the different floral morphs may facilitate outcrossing, and a controlled pollination study found that intermorph pollinations produced the greatest number of seeds, followed by intramorph pollinations and self-pollinations. However, the intramorph pollinations still produced a significant number of apparently viable seeds (statistically greater than the self-pollinations), suggesting that the degree to which heterostyly ensures outcrossing in K. fragrans may be limited. Research on this issue is ongoing (Meinke and Kaye 2007).