| Halesia | |
|---|---|
 | |
| Halesia carolina | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Ericales |
| Family: | Styracaceae |
| Genus: | Halesia J.Ellis exL. |
| Species | |
See text | |
Halesia, also known assilverbell orsnowdrop tree, is a smallgenus of four or five species ofdeciduous largeshrubs or smalltrees in thefamilyStyracaceae.
They arenative to eastern Asia (southeastChina) and easternNorth America (southernOntario,Canada south throughFlorida and easternTexas, United States).
They grow to 5–20 m (16–66 ft) tall (rarely to 39 m (128 ft)), and have alternate, simple ovateleaves 5–16 cm long and 3–8 cm broad. Theflowers are pendulous, white or pale pink, produced in open clusters of 2–6 flowers, each flower being 1–3 cm long. Thefruit is a distinctive, oblong drydrupe 2–4 cm long. All species exceptH. diptera have four narrow longitudinal ribs or wings on fruit;diptera only has two, making it the most distinctive of the group.
Halesia monticola is the largest of the genus, with specimens up to 39 m (128 ft) tall known in theGreat Smoky Mountains National Park inNorth Carolina; the second-largest isH. macgregorii, reaching 24 m (79 ft) in China. The others rarely exceed 10 m (33 ft) tall.H. monticola is considered by some to be a subspecies ofH. carolina (akaH. tetraptera).[3] However, there appears to be a consistent size difference between the two taxa.
The taxonomy and naming of the American species is confused and extensively disputed. The first dispute is over the exact identity of the specimen first named byLinnaeus asH. carolina; some contend that it is the same asH. parviflora,[4][5][6] while others say it is the same asH. tetraptera.[7][8][9] The second dispute is over whetherH. monticola is sufficiently distinct from the other species to merit specific recognition or not (with its varietal placing depending on the above question, too). Neither question has yet been conclusively answered. The treatment here includes bothH. carolina (small) andH. monticola (large).
Aphylogenetic study suggests thatHalesia is notmonophyletic and as a result, the Chinese speciesHalesia macgregorii has been transferred into a new genusPerkinsiodendron, named after American botanist and Styracaceae expertJanet Russell Perkins.[10]
The genus was named afterStephen Hales byJohn Ellis, publishing the name in the tenth edition of Linnaeus'sSystema Naturae in 1759. The name isconserved as the same name had been used in an obscure earlier publication in 1756 for a different plant.[5]
Onefossilendocarp of †Halesia crassa has been described from amiddle Miocenestratum of the Fasterholt area nearSilkeborg in CentralJutland,Denmark.[11]
Silverbells are popularornamental plants in large gardens, grown for their delicate pendant flowers in late spring.
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