Buchnera americana
Buchnera
American bluehearts, bupleurum
bluehearts
simple or branched distally, 3–9 dm, spreading-hirsute proximally, appressed-hirsute or glabrous distally.
erect, not fleshy, glabrate or hispid-hirsute.
much smaller distally;
larger blade: major veins 3, minor veins (0–)2, narrowly ovate to lanceolate, 25–65 x 5–18 mm, margins irregularly dentate, teeth 2–3 mm, apex acute, surfaces short-hispid.
basal and cauline or cauline, opposite or subopposite;
petiole absent or nearly so;
blade not fleshy, not leathery, margins entire, dentate, or crenate.
terminal, spikes or spikelike racemes;
bracts present.
bracts ovate-lanceolate, 4–6 mm.
1–1.5 mm;
bracteoles 2–3 mm.
absent or present;
bracteoles present.
calyx 6–8 mm, tube obscurely 10-nerved, ascending- to appressed-hispid, hairs often pustular-based;
corolla 15–21 mm, glabrate externally, lobes 5–8 mm;
style included, 1–2 mm.
sepals 5, calyx nearly radially symmetric, tubular, lobes narrowly triangular;
petals 5, corolla purple, blue-purple, blue, violet, rosy, or white, bilabiate, salverform, pilose within, abaxial lobes 3, adaxial 2;
stamens 4, subequal, filaments pilose;
staminode 0;
ovary 2-locular, placentation axile;
stigma short-cylindric.
blackish, ovoid, 6–8 mm, glabrate.
dehiscence loculicidal.
0.6–0.8 mm.
ca. 250, dark brown to blackish, cylindric-hexahedral, slightly broader at one end, wings absent.
= 20.
= 40.
Buchnera americana
Buchnera
Buchnera americana has declined significantly in the past century and now is of conservation concern in most states east of the Mississippi River and in Ontario; its current stronghold is in Kansas, Missouri, and Oklahoma. In greenhouse studies, B. americana and B. floridana parasitized a variety of grass and tree species (Celtis, Fraxinus, Liquidambar, Liriodendron, Nyssa, Paspalum, Pinus, Quercus); natural hosts remain largely undocumented (L. J. Musselman and W. F. Mann 1977, 1978). It is nearly restricted to older geological regions away from the coastal plain, primarily in circumneutral to high pH soils; there are records from eastern Texas-central Louisiana, southeastern Louisiana-southern Mississippi, and a few records from northwestern Florida, all apparently in acidic soils. There appears to be no morphological intergradation with B. floridana in those areas, and the occurrence of B. americana there is puzzling.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species ca. 100 (3 in the flora).
In some publications, the honoree of the name Buchnera is given as Johann Gottfried Büchner (1695–1749), German botanist. C. Linnaeus (1738) explicitly stated that the honoree is A. E. von Büchner. Linnaeus omitted this information in 1753 and 1754, thus perhaps opening the door to erroneous etymology.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaves: blades linear to linear-lanceolate, not smaller distally; calyx tubes prominently 10-nerved. | B. obliqua |
1. Leaves: blades narrowly ovate, lanceolate, or narrowly oblanceolate, much smaller distally; calyx tubes obscurely 10-nerved. | → 2 |
2. Leaves: larger blades narrowly ovate to lanceolate, major veins 3, minor veins (0–)2, apex acute, margins irregularly dentate, teeth 2–3 mm; corolla lobes 5–8 mm; calyces 6–8 mm. | B. americana |
2. Leaves: larger blades narrowly oblanceolate, lanceolate, or broadly linear, major veins 1, minor veins (0–)2, apex usually obtuse or rounded, margins entire or crenate, teeth 0.5–1.5 mm; corolla lobes 2–5 mm; calyces 4.5–5.5 mm. | B. floridana |
IL Wildflowers
KS Wildflowers
LA Plants
MD Biodiversity
MI Flora
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
