Halesia

Taxobox
name = "Halesia"

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image_width = 240px
image_caption = "Halesia carolina" (? "H. tetraptera")
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Ericales
familia = Styracaceae
genus = "Halesia" J.Ellis ex L.
subdivision_ranks = Species
subdivision = See text

"Halesia" (Silverbell or Snowdrop Tree) is a small genus of four or five species of deciduous large shrubs or small trees in the family Styracaceae, native to eastern Asia (southeast China) and eastern North America (southern Ontario, Canada south to Florida and eastern Texas, United States). They grow to 5-20 m tall (rarely to 39 m), and have alternate, simple ovate leaves 5-16 cm long and 3-8 cm broad. The flowers are pendulous, white or pale pink, produced in open clusters of 2-6 together, each flower 1-3 cm long. The fruit is an oblong dry drupe 2-4 cm long, with two or four narrow longitudinal ribs or wings.

;Species
*"Halesia carolina" L. - eastern North America (syn. "H. parviflora" or "H. tetraptera")
*"Halesia diptera" Ellis - southeastern North America
*"Halesia macgregorii" Chun - eastern China
*"Halesia monticola" (Rehd.) Sarg.; Mountain Silverbell - eastern North America (syn. "H. carolina" var. "monticola"; "H. tetraptera" var. "monticola")
*"Halesia parviflora" Michx. - eastern North America
*"Halesia tetraptera" Ellis - eastern North America

"H. diptera" is the most distinct, readily distinguished from the other taxa by its two-winged fruit; the other taxa all have four-winged fruit.

"H. monticola" is by far the largest of the genus, with specimens up to 39 m tall known in the Great Smoky Mountains National Park in North Carolina; the second-largest is "H. macgregorii", reaching 24 m in China. The others rarely exceed 10 m tall.

Taxonomy

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 by Linnaeus as "H. carolina"; some contend that it is the same as "H. parviflora", [Reveal, J. L., & Seldin, M. J. (1976). On the Identity of Halesia carolina L. (Styracaceae). "Taxon" 25 (1): 123–140. [http://links.jstor.org/sici?sici=0040-0262%28197602%2925%3A1%3C123%3AOTIOHC%3E2.0.CO%3B2-1&size=LARGE&origin=JSTOR-enlargePage Abstract] ] Germplasm Resources Information Network: [http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?5321 "Halesia"] ] [USDA Plants Profile: [http://plants.usda.gov/java/profile?symbol=HALES "Halesia"] ] while others say it is the same as "H. tetraptera". [Fritsch, P. W. & Lucas, S. D. (2000). Clinal Variation in the Halesia carolina Complex (Styracaceae). "Systematic Botany" 25 (2): 197–210. [http://links.jstor.org/sici?sici=0363-6445%28200004%2F06%2925%3A2%3C197%3ACVITHC%3E2.0.CO%3B2-2&size=LARGE&origin=JSTOR-enlargePage Abstract] ] [Florida Institute for Systematic Botany: [http://www.plantatlas.usf.edu/synonyms.asp?plantID=3261 "Halesia carolina"] ] [U.S. Forest Service Silvics Manual: [http://www.na.fs.fed.us/pubs/silvics_manual/volume_2/halesia/carolina.htm "Halesia carolina"] ] The second dispute is over whether "H. 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 genus was named after Stephen Hales by John Ellis, publishing the name in the tenth edition of Linnaeus's "Systema Naturae" in 1759. The name is conserved as the same name had been used in an obscure earlier publication in 1756 for a different plant.

Cultivation and uses

Silverbells are popular ornamental plants in large gardens, grown for their delicate pendulous flowers in late spring.

References