Ailanthus vilmoriniana is a deciduous tree belonging to the family Simaroubaceae. Native to the mountainous regions of western China, specifically the provinces of Sichuan, Yunnan, and Hubei, it is a member of the genus commonly known as "trees of heaven."
Taxonomy and Etymology
The species was formally described by the French botanist Louis-Albert Dode in 1904. The specific epithet vilmoriniana honors the Vilmorin family, specifically Maurice de Vilmorin, a prominent French dendrologist and seedsman who introduced the species to the West.
The taxonomic status of Ailanthus vilmoriniana is a subject of botanical discussion. Some authorities classify it as a distinct species, while others treat it as a variety of the more common Ailanthus altissima, often designated as Ailanthus altissima var. sutchuenensis.
Morphology
Ailanthus vilmoriniana is a vigorous, fast-growing tree capable of reaching heights between 15 and 25 meters. It shares the general habit of other Ailanthus species, characterized by a broad, open crown and smooth, grey-brown bark that develops fissures with age.
The primary morphological features that distinguish Ailanthus vilmoriniana from Ailanthus altissima involve its pubescence and stem texture. The young branchlets, leaf rachises, and petioles are typically covered in dense, soft hairs (pubescence). Additionally, the young shoots and leaf stalks often feature small, green or reddish prickles, a trait less common or absent in other members of the genus.
The leaves are large, alternate, and odd-pinnate, often reaching 50 to 90 centimeters in length. They consist of 13 to 25 individual leaflets, which are lanceolate and possess a few glandular teeth near the base. When crushed, the foliage emits a pungent, distinctive odor.
Distribution and Ecology
The species is indigenous to temperate and subtropical forests in western China, where it typically grows on mountain slopes or in valleys at elevations ranging from 500 to 2,500 meters. Like its relatives, it is known for its hardiness and ability to grow in various soil types.
Reproduction
Ailanthus vilmoriniana is dioecious, with male and female flowers appearing on separate trees. The flowers are small, greenish-yellow, and arranged in large terminal panicles. The fruit is a samara—a flattened, winged nutlet—approximately 5 centimeters long, which contains a single seed in the center. These wings allow the seeds to be dispersed over long distances by the wind.
Cultivation
While not as widely naturalized or invasive as Ailanthus altissima, Ailanthus vilmoriniana was introduced to European and North American horticulture in the late 19th and early 20th centuries. It is primarily found in botanical gardens and specialized arboreta, valued for its large, tropical-looking foliage and its historical significance in the study of Chinese flora.