buttonbush (Cephalanthus occidentalis)
Cephalanthus occidentalis L. var. californicus Benth.
Cephalanthus occidentalis L. var. pubescens Raf.
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name for buttonbush
is Cephalanthus occidentalis L. Recognized varieties include: 1) Cephal-
anthus occidentalis var. pubescens (Raf.), 2) Cephalanthus occidentalis
var. californicus (Benth.), and 3) Cephalanthus occidentalis var. angust-
ifolius (Dippel). However, the PLANTS Database lists varaieties pubescens
and californicus as synonyms for Cephalanthus occidentalis. The Atlas of
Virginia Flora lists Cephalanthus occidentalis without variety.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Buttonbush is a
deciduous, warm-season, tall shrub or small tree that can reach up to
18 feet (6 m) in height. Its base is often swollen. Branches are usually
green when young but turn brown at maturity. Buttonbush has opposite,
lanceolate-oblong leaves about 7 inches (18 cm) long and 3 inches (7.5 cm)
wide. Tiny, white flowers occur in dense, spherical clusters at the ends of
the branches. Fruits are a round cluster of brown, cone-shaped nutlets.
The variety angustifolius usually has leaves in whorls of threes. The var-
iety pubescens has hairs on the lower leaf surfaces. The variety californicus
has more lanceolate leaves than the other two varieties.
REGENERATION PROCESS: Buttonbush propogates itself by reseed-
ing. Although a prolific seed producer, seeds have a low germination rate.
SITE CHARACTERISTICS: Buttonbush grows along swamps,
marshes, bogs, ditches, and other riparian areas that are inundated
for at least part of the year. It grows in alluvial plains that experience
intermittant flooding, but can be damaged by spring flooding. Button-
bush is very tolerant of flooding and that its abundance increased with
increasing water depth. There is also an increase in buttonbush abun-
dance with an increase in light level. Elevational and geographical distri-
bution of buttonbush may be limited by mean July temperatures of 68
degrees Fahrenheit (20 deg C). Buttonbush was found growing in sandy,
loamy sandy, or alluvial soil with a sandy or silty surface.
SUCCESSIONAL STATUS: Buttonbush is a pioneer species in fre-
quently flooded baldcypress/water tupelo (Nyssa aquatica) swamps,
establishing on rotting logs and stumps. In the Sacremento Valley,
buttonbush/dogwood (Corunus spp.) communities are succeeded by
white alder (Alnus rhombifolia)/willow (Salix spp.)/Oregon ash (Frax-
inus latifolia) and eventually cottonwood (Populus spp.) forests. But-
tonbush also colonizes lowland marsh communities dominated by
hardstem bulrush (Scirpus acutus).
SEASONAL DEVELOPMENT: Buttonbush flowers between June
and September and produces fruit between September and October.
GENERAL DISTRIBUTION: Buttonbush extends from southern Nova
Scotia, New Brunswick, Quebec, and Ontario south through southern
Florida and west through the eastern half of the Great Plains States. Scat-
tered populations exist in New Mexico, Arizona, and the central valley
of California. The variety californicus is found in California; the variety
pubescens is found from southeast Virginia to Georgia and Texas, south-
ern Ontario, Indiana, Illinois, and Oklahoma.
SKY MEADOWS DISTRIBUTION:
Shrub specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: Buttonbush is
a wetland shrub common to most swamps and floodplains of eastern
and southern North America. It is listed as a significant component of
riparian and wetland habitats. Plant communities include Maple - bass-
wood forest, hickory forest, ash forest, Beech - maple forest, Mixed
mesophytic forest, Appalachian oak forest, Mangrove, Northern hard-
woods, Northeastern oak - pine forest, Southern mixed forest, and
Southern floodplain forest.
Common associates of buttonbush include American beech (Fagus
grandifolia), red maple (Acer rubrum), sugar maple (Acer saccharum),
ash (Fraxinus spp.), black oak (Quercus velutina), pin oak (Quercus
palustris), tupelo and gum (Nyssa spp.), baldcypress (Taxodium
distichum), southern bayberry (Myrica cerifera), redbay (Persea
palustris), holly (Ilex spp.), dogberry (Ribes cynosbati), grape (Vitis
spp.), viburnum (Viburnum spp.), poison-ivy (Toxicodendron radicans),
indiangrass (Sorgastrom nutans), big bluestem (Andropogon gerardii),
switchgrass (Panicum virgatum), and sedge (Carex spp.).
IMPORTANCE AND USES: Many species of waterfowl and shore-
birds eat buttonbush seeds. White-tailed deer use of buttonbush browse
varies from light in Pennsyvania to heavy in Nova Scotia. Bees use but-
tonbush to produce honey. Buttonbush is important to wood ducks for
brood rearing and hiding.
The bark of buttonbush was traditionally used for making laxatives, and
for curing skin, bronchial, and venereal diseases. Caution must be used,
however, because the bark contains cephalathin, a poison that can induce
vomitting, paralysis, and convulsions.
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