Rhus typhina

Martha Ruth Wardle

Stag's Horn Sumac or Staghorn Sumac

[Photograph: Ruth Wardle, 8 August, 1997]

Anacardiaceae: Cashew Family

Carl Linnaeus (1707-1778), "a Swedish botanist, physician, and zoologist"Shetler & Skog, 1978 described the typhina species of Rhus. Linnaeus is the "founder of modern plant systematics and nomenclature." (Shetler & Skog, 1978) The names of the species he identified are followed by his initial, L., and specimens of many of these species, most likely this species among them, are located in the Linnaean herbarium at the Linnaean Society of London (LINN). (Shetler & Skog, 1978)

Uses of Rhus typhina:

Its year-round qualities (it is a deciduous tree) make it a valuable landscape plant. (Cross, 1988) It is also attractive, and so is used as an ornamental. It is a hardy tree, too, however, and can grow well in poor, dry or rocky soils. (Cross 1988) However, as of ten years ago, Staghorn Sumac was not being grown by commercial nurserymen. (Cross, 1988)

In invitro studies its inhibitory potential against fireblight, Erwinia amylovora, was found to be comparable with streptomycin. (Acta Horticulturae, 1990)

Diagnostic Characteristics of Rhus typhina:

• Branches and Twigs:
• covered with brown felt-like growth of hairs
• resemble the antlers of a stag in velvet (Leathert, 1977)
• Bark:
• with horizontal lenticels (Duncan & Duncan, 1988)
• Fruits and Flowers:
• fruits are 2-5 mm across, covered with red hairs and in terminal clusters as can be seen in the photo below (Duncan & Duncan, 1988)
• flowers are also in terminal clusters; male and female flowers are usually on separate plants (Duncan & Duncan, 1988)
• Sap:
• sap is milky at first but turns dark upon exposure to air (Duncan & Duncan, 1988)
• it is hard to wash off if it gets on the hands (Cross, 1988)
• some people have allergic reactions to the sap (Cross, 1988)
• Branching Patterns and Tree Size:
• can be a low shrub or a tree up to 15 m tall by 32 cm DBH, but usually considerably smaller
• sprouts abundantly from the roots
• forms thickets (Duncan & Duncan, 1988)

[Photograph: Ruth Wardle, 8 August, 1997]

Life Cycle

• sprouts are visible ~ 1 month after planting
• leaves turn in early fall
• leaves are lost with the first frosts of the winter, the month varying with location
• the trees have developed to their full potential for that particular growing season six months after planting; one stem is produced
• if the trees go through another growing season they will produce one or two more stems (Cross 1988)

Directions for finding Rhus typhina in Athens, Clarke County, Georgia:

From Broad Street in downtown Athens, drive south on Thomas Street. After going down the first hill, at the intersection of Mitchell Street and Thomas Street look toward the southwest corner of the intersection. A grove of Stag's Horn Sumac lies between Mitchell and Thomas Streets adjacent to the parking lot for the Mitchell Services Building of the University of Georgia.

During late summer the clusters of fruit are prominent on the sumac trees and make identification easy because they are large, red, and visible, being on the ends of the twigs and sticking up. Also, the compound leaves with 10-30 leaflets have a characteristic appearance that makes them simple to identify.