Heracleum sibiricum
Heracleum sibiricum is a species of flowering plant in the family Apiaceae. It is native to Europe and western Asia, ranging from France and Italy to western Siberia and Mongolia.
Description
Heracleum sibiricum is a herbaceous, perennial, flowering plant with flowers arranged in an umbel. Each flower has five yellowish-green petals. Individual flowers may be bisexual, pistillate, or staminate. The pistil is bicarpellate and syncarpous, that is, it has two carpels fused together. The ovary is glabrous and the stylopodium is almost always green. The fruit is composed of two mericarps, each with a single seed.Similar species
Heracleum sibiricum is similar in appearance to Heracleum sphondylium, a very close relative. The following table emphasizes the differences between the two species:| Heracleum sphondylium | Heracleum sibiricum | |
| Flower color | White, rarely yellowish, greenish, or pink | Greenish-yellow or greenish, never white |
| Floral symmetry | The outer petals of the marginal flowers of a secondary umbel are enlarged, often two or more times longer than the inner petals; the outer petals are deeply incised at apex | The outer petals of the marginal flowers of a secondary umbel are not enlarged or only very slightly enlarged; the outer petals are either not incised at the apex or only slightly incised |
| Ovary | Overgrown with soft, spreading hairs with blunt tips | Glabrous |
| Stylopodium | Almost always whitish | Almost always greenish |
The marginal flowers of Heracleum sphondylium are typically zygomorphic, whereas the marginal flowers of Heracleum sibiricum are actinomorphic or nearly so. Occasionally the marginal flowers of Heracleum sphondylium will be actinomorphic, however.
Both species are variable with respect to the pilosity of the ovary. An atypical form of Heracleum sphondylium may appear to be glabrous to the naked eye but in fact it has short, stiff, ascending hairs with pointy tips. An atypical form of Heracleum sibiricum has similar but even shorter hairs.
Taxonomy
Heracleum sibiricum is one of five species of Heracleum described by the Swedish botanist Carl Linnaeus in 1753. The specific name sibiricum suggests the taxon occurs in Siberia, a fact mentioned by Linnaeus in his description. In 1887, the Hungarian botanist Lajos Simonkai reduced its taxonomic rank to a subspecies of Heracleum sphondylium., Plants of the World Online accept Heracleum sibiricum, but most authorities still recognize Heracleum sphondylium subsp. sibiricumIn 1926, the Swiss botanist Albert Thellung described Heracleum sphondylium var. chaetocarpum, a variety of Heracleum sibiricum. Thellung described the taxon as a variety of Heracleum sphondylium since he recognized Heracleum sphondylium subsp. sibiricum . The typical form of Heracleum sibiricum has a glabrous ovary, whereas that of var. chaetocarpum has short, stiff, ascending hairs with pointy tips. The hairs are so short and sparse, they may not be visible to the naked eye. In 1961, the Polish botanist Maria Gawłowska described Heracleum sibiricum f. rarum, a form of var. chaetocarpum with elongated leaf lobes.