Montana Field Guide

PLANTS: Perennial herbs with leafy stems that are 20-100 cm tall and which arise from short rhizomes. Source: Hitchcock et al. 2018.

LEAVES: The leaves are 6-10 cm long and lanceolate to ovate. Blades are cauline, without petioles, and clasping the stem. Source: Hitchcock et al. 2018.

INFLORESCENCE: A long, narrow, few to 20 flowered, leafy-bracted raceme located at the tops of the stems. Flowers are bilaterally symmetrical with long green sepals and shorter, broader, reddish petals.

The specific epithet helleborine is Latin meaning “like Helloborus” referring to the genus Helleborus in the family Ranunculaceae. Both plants have poisonous qualities. Epipactis is derived from the ancient Greek word epipaktis which was the common name for hellebore, a genus in the Ranunculaceae family that bears some similarities to Epipactis species (Giblin et al. [eds.] 2018).

Flowering June through October (Brown in Flora of North America (FNA) 2019).

Montana has two species of Epipactis, one native, E. gigantea, and one non-native, E. helleborine. Both species are perennial herbs with bilaterally symmetrical flowers borne in leafy-bracted terminal racemes.

Eastern Helleborine - Epipactis helleborine, non-native
*Size: Mature plants are 20-100 cm tall.
*Leaves: Lanceolate to ovate blades that are 6-10 cm long.
*Sepals: Green with no or very faint brown veins. Lateral sepals are 6-13 mm long.
*Petals: Lateral petals 8-11 mm long, ovate, and pinkish.
*Lip: Lip petal 9-12 mm long, pouch-like, and not grooved on the tip (not lobed). Petal is purplish-green with saccate portion that is purplish and indistinctly veined.
*Fruit: An ellipsoid capsule that is 9-14 mm long.

Giant Helleborine - Epipactis gigantea, native, SOC
*Size: Mature plants are 30-120 cm tall.
*Leaves: Lanceolate to elliptic blades that are 6-15 cm long.
*Sepals: Green with obvious brown veins. Lateral sepals are 12-24 mm long.
*Petals: Lateral petals 13-15 mm long, ovate, and pinkish.
*Lip: Lip petal 14-20 mm long, concave, and grooved on the tip (lobed). Petal is orangish-yellow with a saccate portion that is purplish veined.
*Fruit: An ovoid to ellipsoid capsule, glabrate, that is 2-3 cm long.

In Montana this plant has not been documented. In other states is has been found growing in shaded woodlands and roadsides (Giblin et al. [eds.] 2018) or on dry slopes or road cuts at less than 1300 m in elevation (Wilken & Jennings 1993).

POLLINATION
A study on native populations in Poland found that the primary pollinator of Eastern Helleborine are hoverflies (Syrphidae), followed by mosquitos (Culicidae), wasps (Vespidae), bees (Apidae), and ants (Formicidae) (Rewicz et al. 2017). This suggests that Eastern Helleborine is opportunistic when considering pollinator species. Furthermore, individuals found in anthropogenic habitats had a greater diversity of pollinator visits than did those found in natural, woodland habitats. (Rewicz et al. 2017).

While Eastern Helleborine clearly has a great diversity of suitable pollinators, many studies have shown that this species is also autogamous (Rewicz et al. 2017). However, autogamy may be a trait that is only selected for when these suitable pollinators are limited or lacking (Ehlers et al. 2002). Some orchid species including Epipactis spp. have specialized, sticky pollinia structures called viscidium that help them to attach to pollinators. In areas where pollinators are not present, and individuals exhibit autogamy, these structures are lacking (Ehlers et al. 2002).

REPRODUCTIVE SUCCESS
Perhaps due to the greater number of pollinator visits and species in addition to larger plant size, reproductive success of plants in anthropogenic habitats is significantly higher than that of plants observed in natural habitats (Rewicz et al. 2017).

Reproductive success may be influenced by flower characteristics due to their relationship with pollinator attraction and pollinia transfer (Ehlers et al. 2002). The number of flowers on a plant is positively correlated with the number of pollinia removed by pollinators and with the number of fruits produced. Pollinia removal is also positively correlated with population size implying that larger populations may have greater reproductive success.

CHLOROPHYLL-FREE VARIATION
A form of Eastern Helleborine that lacks chlorophyll has been observed in Finland (Salmia 1986). The white individuals are formed as raments of regular plants and have a life cycle quite different than that of their parent. They first exist underground as chlorophyll-free mycorrhizomes for several years. Once they emerge above ground, the first inflorescence does not develop for several more years. The occurrence of white plants is positively correlated with favorable weather conditions.

FLOWERS [Wilken & Jennings 1993]
Flower bracts are linear to narrowly lanceolate. Sepals are 10-13 mm long and green with a purple tinge especially on the outside. Lateral petals are 8-11 mm long. The lip petal is 10-12 mm long, the lower half pouch-like, white to pinkish on the outside and brown to purplish on the inside. The upper half of the lip petal is more or less flat and white to pinkish with 2 thick bumps near the base.

FRUIT [Giblin et al. [eds.] 2018]
Mature fruit are 1-1.5 cm long capsules. The capsules are elliptic, green, ridged, and often hairy. They contain many seeds.

LIFE CYCLE [Arditti et al. 1981]
Fertilized seeds require interaction with mycorrhizal fungi in order to germinate and develop a protocorm. Once germinated, the seeds may lay dormant for several years. The protocorm will begin to produce root hairs when it is ready to develop and then emerge above ground as a seedling. Once a plant matures it may reproduce vegetatively by rhizomes.

While considered “naturalized” in its non-native range in North America, Eastern Helleborine has a high potential for becoming invasive (Huebner 2007). In Ontario, the species has spread aggressively since its first recorded occurrence in 1890 (Soper et al. 1985). Limited research has been done on the effects of Eastern Helleborine on native ecosystems, and further study would help inform management decisions.

Population sizes and regular feeding patterns of a native species of weevil, Stethobaris ovata, may alter in the presence of Eastern Helleborine (Morgan 2016). As one of its preferred food sources, Eastern helleborine attracts greater than normal amounts of weevils and may cause probability of damage to native orchids in the area to increase significantly.