Solidago houghtonii

Torrey & A. Gray in A. Gray

in A. Gray, Manual, 211. 1848.

Common names: Houghton’s goldenrod
Endemic
Synonyms: Aster houghtonii (Torrey & A. Gray) Kuntze Oligoneuron houghtonii (Torrey & Gray) G. L. Nesom
Treatment appears in FNA Volume 20. Treatment on page 165. Mentioned on page 163, 166.

Plants 30–60+ cm; caudices branching; vascular-bundles and petiole bases marcescent (attached to old stems for more than a season). Stems 1–5+, erect, slender, glabrous. Leaves: basal tapering to long, winged petioles, blades ovate, to 7–22 mm wide, margins entire, apices acute, faces glabrous; proximal cauline tapering to winged petiolelike bases partially clasping stems, blades sometimes 3-nerved (2 prominent lateral nerves arising proximally and running alongside midnerve for some distance before diverging), linear-oblanceolate, 158–177 × 7–22 mm, margins entire, ciliate, apices acute to obtuse, glabrous; mid to distal sessile, blades linear-lanceolate, mid often 3-nerved (obscurely sometimes), distal 1-nerved, 47–100 × 4–10 mm, reduced distally. Heads (2–) 5–50 (–100+), not secund, in corymbiform arrays, branches and peduncles glabrous or moderately strigillose. Peduncles 5–6.2 mm, sparsely to moderately strigillose; bracteoles 0–2, linear. Involucres campanulate, (5.5–) 6–8 (–9) mm. Phyllaries in 3–4 series, unequal, linear to oblanceolate, margins ciliate, weakly striate, obtuse to rounded. Ray-florets 6–12 (pale to bright-yellow); laminae 7.4–7.9 × 0.5–0.6 mm. Disc-florets 8–15; corollas 4–4.3 mm, lobes 0.9–1.5 mm. Cypselae obconic, 1.4–1.8 mm, glabrous, ribs sometimes dark; pappi of bristles 4–5.5 mm, clavate. 2n = 54.


Phenology: Flowering Aug–Sep.
Habitat: Damp, interdunal hollows, limestone pavements (alvars)
Elevation: 100–400 m

Discussion

The large involucres and the presence of the unique 3-nerved proximal and mid cauline leaves distinguish Solidago houghtonii from other taxa in sect. Ptarmicoidei. The 3-nerved venation pattern may be morphologic evidence of a hybrid origin for S. houghtoni between a parallel-nerved member of sect. Ptarmicoidei and a 3-nerved member of subsect. Triplinerviae. Molecular data indicate that S. gigantea may have been one of the parental species (P. Laureto, pers. comm.).

Reports of Solidago houghtonii from New York have been rejected as being based on misidentified specimens (J. K. Morton 1979). Some collections have the large involucres typical of S. houghtonii; molecular data indicate that the species is present in Genessee County, New York (P. Laureto, pers. comm.).

Solidago houghtonii can be difficult to distinguish from S. ohioensis × S. ptarmicoides hybrids because both have hairy peduncles in arrays. The hybrids have pale yellow rays even when fresh; post-flowering rays of S. houghtonii can be pale yellow. J. K. Morton (1979) hypothesized an allopolyploid origin for the hexaploid S. houghtonii via an unreduced gamete of S. ohioensis × S. ptarmicoides backcrossed to S. ohioensis with subsequent chromosome doubling. Additional work is needed to confirm this hypothesis. An aberrant collection (M. R. Penskar 1067, MICH) had about 400 heads (mostly in bud) due to axillary branches developing along nearly the entire stem; stems usually have fewer than 50 heads. Some plants from Michigan are more robust than those found in Ontario.

Solidago houghtonii is listed by the U.S. Fish and Wildlife Service as threatened in Michigan. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Selected References

None.

Lower Taxa

None.
... more about "Solidago houghtonii"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
indeterminate +  and determinate +
flat-topped +  and rounded +
John C. Semple +  and Rachel E. Cook +
Torrey & A. Gray in A. Gray +
decurrent +
Aster sect. Ptarmicoidei +
15.8 cm158 mm <br />0.158 m <br /> (17.7 cm177 mm <br />0.177 m <br />) +
linear-lanceolate;linear-oblanceolate;ovate +
7mm;22mm +
rugulose +  and muricate +
0.4 cm4 mm <br />0.004 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
Houghton’s goldenrod +
not 2-lipped +  and actinomorphic +
yellow +  and white +
ampliate +
0.4 cm4 mm <br />0.004 m <br /> (0.43 cm4.3 mm <br />0.0043 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
fertile +  and bisexual +
fertile +  and bisexual +
4.7 cm47 mm <br />0.047 m <br /> (10 cm100 mm <br />0.1 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (?) +  and 1 cm10 mm <br />0.01 m <br /> (?) +
Ont. +, Mich. +  and N.Y. +
100–400 m +
resinous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Damp, interdunal hollows, limestone pavements (alvars) +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.8 cm8 mm <br />0.008 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
campanulate +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.17 cm1.7 mm <br />0.0017 m <br /> (1 cm10 mm <br />0.01 m <br />) +
7.4mm;7.9mm +
0.5mm;0.6mm +
erect;spreading +
triangular +  and narrowly lanceolate +
obtuse +  and rounded +
linear-lanceolate +  and oblong or ovate +
unequal +  and rarely subequal +
2-carpellate +
persistent +
strigillose +  and glabrous +
0.5 cm5 mm <br />0.005 m <br /> (0.62 cm6.2 mm <br />0.0062 m <br />) +
Flowering Aug–Sep. +
linear +  and oblanceolate +
ovate-oblanceolate +
tapering +  and winged petiolelike +
in A. Gray, Manual, +
bearing subulate enations +, hairy +  and bristly +
strigillose +  and glabrous +
8 +  and 10 +
exalbuminous +
1 +  and 5 +
slender +
appendaged +  and truncate +
papillate +  and smooth +
Aster houghtonii +  and Oligoneuron houghtonii +
Solidago houghtonii +
Solidago sect. Ptarmicoidei +
species +
100 cm1,000 mm <br />1 m <br /> (200 cm2,000 mm <br />2 m <br />) +
5 cm50 mm <br />0.05 m <br /> (100 cm1,000 mm <br />1 m <br />) +