Astilbe biternata

(Ventenat) Britton ex Kearney

Bull. Torrey Bot. Club 20: 475. 1893,.

IllustratedEndemic
Basionyms: Tiarella biternata Ventenat Jard. Malmaison 1: plate 54. 1804
Synonyms: Astilbe crenatiloba (Britton) Small
Treatment appears in FNA Volume 8. Treatment on page 129.

Leaves coarse, terminal leaflets usually 3-lobed, or at least 2-lobed, even if weakly or unevenly; petiole, rachis, and petiolules usually stipitate-glandular. Leaflets petiolulate; blade ovate, 8–15 × 4–15 cm, base usually cordate, rarely cuneate, margins sharply serrate to crenate, apex acuminate. Flowers: sepals persistent, triangular, 0.7–1.5 mm; petals 5 or absent in pistillate flowers, erect, spatulate to subulate, 1.5–4 mm. Capsules partly connate, or separating as 2 follicles, 3.5–4 mm. Seeds 5–10, linear, 1.5–2 mm. 2n = 28.


Phenology: Flowering Jun.
Habitat: Rich woods and shaded north-facing road banks, ditches and seeps
Elevation: 300-1200 m

Distribution

V8 258-distribution-map.gif

Ga., Ky., N.C., S.C., Tenn., Va., W.Va.

Discussion

Astilbe biternata is known from the southern Appalachian Mountains from Mingo County, West Virginia, through Virginia and Kentucky to the Carolinas, Tennessee, and northwestern Georgia.

Elegant when in flower, although rarely cultivated, Astilbe biternata is often confused with goat’s-beard, Aruncus dioicus (Walter) Fernald (Rosaceae), which grows in identical habitats and often side-by-side. Remarkably, both are dioecious with relatively large compound leaves and terminal panicles of relatively small, white, unisexual flowers. Elsewhere in the world, Astilbe species generally have bisexual flowers; Aruncus dioicus is dioecious around the world. Astilbe biternata flowers just after Aruncus, and may be further distinguished by its three-lobed terminal leaflets, glandular hairs, ten rather than 15 stamens, and usually two- rather than three-carpellate fruits.

Astilbe crenatiloba has been recognized from the rich, wooded lower slopes of the Tennessee side of Roan Mountain on the North Carolina–Tennessee border as being shorter, with crenate leaves, and fruits to 3 mm long. Although it seems to have distinctive features, it may be just a local variant. It is represented only by its original two herbarium specimens and has not been seen since its discovery, published in 1888, despite repeated searches.

Selected References

None.

Lower Taxa

None.

... more about "Astilbe biternata"
epigynous +, perigynous +  and hypogynous +
T. Lawrence Mellichamp +
(Ventenat) Britton ex Kearney +
cuneate +  and cordate +
Tiarella biternata +
8 cm80 mm <br />0.08 m <br /> (15 cm150 mm <br />0.15 m <br />) +
dentate +, serrate +  and entire +
glandular-ciliate +  and ciliate +
4cm +  and 15cm +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
3-carpellate +  and 2-carpellate +
ebracteate +, bracteate +  and 2-300(-1000+)-flowered +
Ga. +, Ky. +, N.C. +, S.C. +, Tenn. +, Va. +  and W.Va. +
300-1200 m +
bisexual +  and unisexual +
150 cm1,500 mm <br />1.5 m <br /> (200 cm2,000 mm <br />2 m <br />) +
2-3(-4)-beaked +  and folliclelike +
Rich woods and shaded north-facing road banks, ditches and seeps +
multicellular +  and unicellular +
multiseriate +  and uniseriate +
greenish whitish +
free +  and adnate +
simple +, compound +  and decompound +
opposite +  and alternate +
cauline +  and basal +
glabrous +  and short-stipitate-glandular +
sharply serrate +  and crenate +
1 cm10 mm <br />0.01 m <br /> (?) +
crassinucellate +, unitegmic +  and bitegmic +
bracteate +  and 500-2000-flowered +
spikelike +  and plumose +
epigynous +, perigynous +  and hypogynous +
distinct +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
glandular-stipitate +
stipitate-glandular +
stipitate-glandular +
Flowering Jun. +
2(-3)-carpellate +
unequal +
Bull. Torrey Bot. Club +
stipitate-glandular +
spiny +  and ribbed +
straight +
wrinkled +  and striate +
oblong-cylindric +
persistent +
distinct +
triangular +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Illustrated +  and Endemic +
unbranched +  and branched +
persistent +
horizontal +  and erect +
connate +  and distinct +
Astilbe crenatiloba +
Astilbe biternata +
species +
2-lobed +  and 3-lobed +
mucronate +
not stoloniferous +  and not rhizomatous +
annual +, biennial +  and perennial +
plant +, herb +  and clump-forming +
polygamous +  and dioecious +