Aruncus dioicus
Aruncus
bride's feathers, buck's-beard, goat's-beard, sylvan goatsbeard
aruncus, barbe-de-bouc, bride's-feathers, goat's-beard
1–5, erect, stout, simple, sometimes glaucous.
leaflets green to gray-green, 6–15 cm, base subcordate to attenuate, apex acute to long-acuminate.
deciduous, cauline, alternate, 2–3-irregularly ternate to odd-pinnate, equivalent to 2–3 pinnate;
petiole present, relatively long, base 1/2 sheathing stems;
blade broadly ovate, cauline reduced in size and complexity distally, 15–60 cm, thick to thin, leaflets 9–45, long-petiolulate, broadly ovate to narrowly lanceolate, margins flat, [serrate to] doubly serrate, venation pinnate.
terminal, 500–2500-flowered, racemes forming panicles;
bracts present;
bracteoles present hairs simple, glandular.
present.
sepals 1 mm;
petals 0.5–1.5 mm, apex acute to obtuse;
stamens 1.5–2 mm, filaments slender, ± equal, anthers versatile;
styles [0.2–]0.3–0.8 mm.
unisexual (plants dioecious, rarely polygamous), 3–4 mm diam.;
epicalyx bractlets 0;
hypanthium shallowly bowl-shaped, 0.5–1 mm, nectary ring inside with simple, glandular hairs;
sepals persistent, 5, spreading, triangular, margins entire;
petals 5, white, obovate to elliptic, base cuneate; staminate: stamens (15–)20(–30) in 1 series (between calyx and nectar ring), longer than petals;
torus minute; pistillate: nectar ring scarcely developed, stamens rudimentary, carpels 3, free, glabrous, styles terminal;
ovules 2–4.
follicles, 3(or 4), pedicels recurving, fruits inverted, retrorse, ovate-elongate, 1.5–5 mm, shining, glabrous, dehiscent along whole adaxial suture;
hypanthium persistent;
sepals persistent, spreading to appressed;
styles persistent, forming a beak.
1.5–2(–2.5) mm.
2–4, elongate, membranous, caudate at both ends, scalariform-reticulate, seed coat loose.
= 7, 9.
Aruncus dioicus
Aruncus
Varieties 14 (4 in the flora).
Aruncus dioicus is superficially similar to Astilbe biternata (Saxifragaceae), false goat’s-beard, which is endemic to the southern Appalachian Mountains. Both species produce tall, dioecious plants with biternately to bipinnately compound leaves and plumelike terminal panicles with many, relatively small white, unisexual flowers, and may grow side by side. Aruncus dioicus is more widespread and may be readily distinguished by its unlobed rather than 3-lobed terminal leaflets, flowers with 20 rather than 10 stamens, and 3 carpels reflexed in fruit rather than 2 erect carpels. See T. L. Mellichamp (1976) for an analysis of this remarkable example of convergent evolution.
Aruncus dioicus is striking and is grown in gardens throughout North America. It is variable throughout the temperate and subarctic regions of the Northern Hemisphere, especially in China and Japan. H. Hara (1955) recognized the following varieties that are found in the flora area.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 1.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Follicles 1.5–2.4 mm; styles 0.3–0.8 mm; seeds 1.5–2 mm | → 2 |
1. Follicles 2.5–5 mm; styles 0.3–0.5 mm; seeds 1.8–2.5 mm | → 3 |
2. Follicles 1.5–2 mm; leaf surfaces glabrous or slightly hairy; s Appalachians and eastward. | var. dioicus |
2. Follicles 1.6–2.4 mm; leaf surfaces densely hairy; w of Appalachians. | var. pubescens |
3. Follicles 2.5–5 mm; Alaska and Yukon to n California. | var. acuminatus |
3. Follicles 2.5–3 mm; introduced, ne United States. | var. vulgaris |
- Local floras:
BC, 
OR, 
WA - Local Web sites:
CalFlora, CalPhotos, 
Flora NW, 
Go Botany, 
IL Wildflowers, 
MD Biodiversity, 
MI Flora, 
MO Plants, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
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- Encyclopedia of Life
- Wikipedia
- Google Image Search
