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Key to Solidago
2 Heads borne in cylindrical and thyrsoid arrays, the central axis being the upper stem, the lateral branches of the array of similar length to one another and subtended by either well-developed leaves (longer than the branch) or smaller bracts (shorter than the branch). | |
3 Leaves generally many- and sharp-toothed; achenes persistently pubescent; outer phyllaries with appressed tips; [subgenus Pleiactila; section Glomeruliflorae]. | |
2 Heads borne in paniculiform arrays (with longer lateral branches towards the middle or the base of the array, the heads on at least the longer branches secund). | |
4 Leaves with only the midvein readily apparent; leaves entire; leaf surfaces finely translucent punctate (most obviously seen with transmitted light or with 10× magnification); fresh leaves usually anise-scented; [subgenus Triactis, section Odorae]. | |
4 Leaves either triple-veined or pinnately-veined; leaves entire or often at least obscurely toothed; leaf surfaces not translucent punctate; fresh leaves not anise-scented. | |
5 Leaves pinnately veined; leaves mostly 1-5× as long as wide; [subgenus Pleiactila, section Venosae]. | |
6 Heads borne in corymbiform arrays, flat-topped or broadly rounded; array of heads about as broad as long, or broader. | |
7 Larger leaves obovate, 5-10 cm long, 1.5-4 cm wide, with prominent teeth; plants small, 0.5-4 dm tall; [high elevation rock outcrops on Grandfather Mountain, Roan Mountain, and Hanging Rock Mountain (Avery, Watauga, and Mitchell counties, NC, and Carter County, TN)]; [subgenus Pleiactila, section Multiradiatae] | |
7 Larger leaves elliptic-oblong, linear, or lanceolate, 6-25 cm long, 0.1-10 cm wide, with small, obscure teeth; plants more robust, 4-15 dm tall; [of low elevations]; [subgenus Pleiactila, section Ptarmicoidei] | |
6 Heads either borne in 1-several thyrsiform (cylindrical) arrays (the heads on short lateral axes about even in length from top to bottom of the array, the heads not secund), or in paniculiform arrays (with longer lateral branches towards the middle or the base of the array, the heads on at least the longer branches secund); array of heads usually much or at least somewhat longer than broad. | |
8 Petioles of the lower stem leaves sheathing the stem (appressed to it and curving around one side of it); leaves basally disposed, the leaves up the stem very many in most species, ascending or appressed, sometimes fewer and more widely spaced; inflorescence either narrowly cylindrical or with well-developed branches with heads secundly arrayed; plants of permanently or seasonally saturated wetlands (bogs, fens, seeps, wet pinelands, marsh edges), or of maritime habitats, or less typically of xerohydric acid flatwoods; [subgenus Pleiactila, section Maritimae]. | |
8 Petioles of the lower stem leaves sessile (not sheathing, but auriculate-clasping at a ca. 90 degree angle to the stem in S. auriculata); leaves basally disposed, the leaves up the stem not very many and with short internodes in most species; inflorescence cylindric or paniculiform; plants of uplands, bottomlands, and sometimes seasonally saturated wetlands (bogs and fens). | |
9 Heads borne in paniculiform arrays (with longer lateral branches towards the middle or the base of the array, the heads on at least the longer branches secund) | |
9 Heads borne in a cylindrical and thyrsoid array, the central axis being the upper stem, the lateral branches of the array of similar length to one another and subtended by either well-developed leaves (longer than the branch) or smaller bracts (shorter than the branch). | |
11 Heads very large, involucre 8-13 mm high; fresh leaves noticeably thick and rubbery in texture; [subgenus Pleiactila; subsection Glomeruliflorae]; [high elevations of NC and TN] | |
![]() Show caption*© Tara Rose Littlefield, some rights reserved (CC BY-NC), uploaded by Tara Rose Littlefield | |
12 Phyllaries and often also vegetative parts with minute sticky glands (use at least 10× magnification); stem leaves petiolate. | |
14 Phyllaries stipitate-glandular (use 10× magnification); [outer Coastal Plain of se. NC]; [subgenus Solidago, section Villosicarpae] | |
Key to Solidago, Key A: Key to "thyrsiflorous goldenrods" -- with stem leaves dominant and cylindrical inflorescences [subgenus Solidago, sections Thyrsiflorae (mostly) and an Erectae]
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2 Leaves oblanceolate-obovate, often short acuminate at the apex; mid-stem leaves 8-14 cm long, 18-40 mm wide, the margins sharply serrate on at least the upper 2/3 | |
3 Middle and inner series phyllaries glabrous, usually minutely glandular or resinous and shiny; mid and upper stem leaves usually narrowly lanceolate, rarely broadly lanceolate to ovate, green to shiny silvery; [MO to LA west to e. KS to se. and c. TX, disjunct in n. COA] | |
3 Middle and inner series phyllaries sparsely to moderately strigose, sometimes minutely glandular; mid and upper stem leaves lanceolate-elliptic to ovate-elliptic; [NC to n. FL west to AL; e. KS, e. OK, c. TX westwards] | |
4 Involucres at anthesis (4.3-) avg. 5.3 (-7) mm high; [e. KS, e. OK, c. TX westwards] |
Key to Solidago, Key B: Key to "axillary forest goldenrods" -- with stem leaves dominant (mostly) and heads axillary to well-developed leaves
[subgenus Pleiactila, section Glomeruliflorae
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![]() Show caption*© Michael John Oldham, some rights reserved (CC BY-NC), uploaded by Michael John Oldham | |
3 Lower midstem leaves narrowly lanceolate, 5-15 cm long, 0.8-3 cm wide, 5-6× as long as wide; stems strongly arching; plants growing singly; [widespread in our area] | |
3 Lower midstem leaves broadly lanceolate to rhombic, 5-9 cm long, 1.3-2.4 cm wide, 3-4× as long as wide; stems weakly arching; plants usually strongly clonal, forming relatively dense patches; [Coastal Plain, NC to FL, west to LA and AR] | |
2 Stem striate-angled, green. | |
6 Leaves 1-2.2 (-2.5)× as long as wide, abruptly contracted to a winged petiole; teeth of the leaf margins elongate and narrow, acuminate, mostly (2-) 3-8 mm long (as measured on the upper side of the tooth) | |
8 Plants solitary; involucres (5-) 5.6-7 (-8) mm high, eglandular; phyllaries 0.7-1 mm wide, usually 1-nerved; stems 4-9 (-10) dm tall; ray flowers 2-4 (-6); [broadly Appalachian] | |
8 Forming dense, clonal colonies from thick, creeping rhizomes; involucres 6.4-8.5 (-9) mm high, glandular pubescent; phyllaries 1-1.5 mm wide, usually 3-10-nerved; stems (2-) 7-16 dm tall; ray flowers 5-8; [apparently restricted to high elevations in the Blue Ridge of w. NC, e. TN, and sw. VA] |
Key to Solidago, Key C: Key to "licorice goldenrods" -- with stem leaves dominant and heads in paniculiform arrays, the leaves translucent dotted and entire [subgenus Triactis; section Odorae]
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1 Main leaves ovate to lanceolate, 2-5 (-6)× as long as wide; stem pubescence general and circumferential; [of FL] | |
1 Main leaves lanceolate to linear, (4-) 5-15× as long as wide; stem pubescence in lines decurrent down the stem from the margins of the leaf bases; [widespread] |
Key to Solidago, Key D: Key to "rugosa goldenrods" -- with pinnately-veined stem leaves dominant and well-developed paniculiform inflorescences [subgenus Pleiactila; section Venosae]
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2 Leaf venation not notably reticulate; plants to 12 dm tall, from a compact caudex; [subgenus Pleiactila, section Venosae, subsection Ulmifoliae]. | |
4 Midstems densely pubescent; midstem leaves with attenuate to rounded bases; midvein of phyllaries as wide or wider than the tissue on each side (midveins of phyllaries equal or greater than 1/3 the phyllary width; [mainly Interior Highlands of AR and MO, rarely disjunct eastwards] | |
4 Midstems glabrous to sparsely pubescent; midstem leaves acuminate; midvein of phyllaries narrower than the tissue on each side (midveins of phyllaries 1/3 to 1/5 the phyllary width); [widespread in our region] | |
2 Leaves pinnately veined and also forming a prominent reticulum, the veins (primary, secondary, and tertiary) very evidently raised on the undersurface (less obviously so in S. fistulosa); plants to 30 (-40) dm tall, from long-creeping rhizomes, thus forming clonal patches; [subgenus Pleiactila, section Venosae, subsection Venosae]. | |
6 Involucres 4-6 mm high; broader phyllaries 0.7-1.2 mm wide; stems glabrous below the inflorescence; mid-stem leaves elliptic (widest near the middle) | |
6 Involucres (2-) 2.5-3.5 (4.5) mm high; phyllaries mostly < 0.5 mm wide; stems hairy or glabrous below the inflorescence; mid-stem leaves lanceolate to ovate (widest below the middle). | |
8 Stem glabrous throughout (except for scattered hairs in inflorescence), stem with striate ridges decurrent from leaf bases; leaf blades appressed serrate (teeth short), blades glabrous beneath except for sparse, short, appressed, straight hairs; early blooming (1 month earlier than S. rugosa in same area); [permanently saturated, ± forested wetlands with Sphagnum moss, such as red maple-Atlantic white cedar swamps, streamhead pocosins, montane bogs] | |
8 Stem pubescent with crinkly hairs throughout (occasional plants varying to glabrate below), stem without striate ridges decurrent from leaf bases; leaf blades sharply serrate (teeth coarse), blades villous to crinkly hairy beneath; late blooming (ca. 1 month later than S. aestivalis in same area); [dry to moist fields, meadows, and other open habitats] | |
10 Upper stem leaves ovate, much reduced relative to leaves lower on the stem |
Key to Solidago, Key E: Key to "tall goldenrods" -- with 3-veined stem leaves dominant and secund paniculiform inflorescences [subgenus Pleiactila; section Unilaterales (in part)]
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3 Rootstock short and branched, not producing creeping rhizomes; ray flowers 5-8; receptacle lacking intercalated green bracts (resembling phyllaries) inward from the rays; mid and upper stem leaves usually lacking axillary fascicles of smaller leaves; [subgenus Pleiactilis, section Unilaterales, subsection Radulae] | |
3 Rootstock producing creeping rhizomes; ray flowers 7-13; receptacle often with a few intercalated green bracts (resembling phyllaries) inward from the rays; mid and upper stem leaves usually with axillary fascicles of smaller leaves; [subgenus Pleiactilis, section Unilaterales, subsection Junceae] | |
1 Upper stem hairy (above the midpoint, up to the branches of the inflorescence), variously puberulent, strigillose to strigose, villous, or scabrous. | |
6 Leaf surfaces with appressed (strigillose) hairs; upper stem vestiture densely strigose, the stems appearing grayish-green; rhizomes long-creeping, the plants forming clonal patches; [OK and nc. TX westwards and northwestwards] | |
6 Leaf surfaces scabrous; upper stem vestiture scabrous to loosely puberulent, the stems appearing green or dingy green; rhizomes short (less commonly moderately creeping); [se. KS, OK, and TX eastwards] | |
7 Rays 2-8; midstem leaves 4-15 mm wide, mostly 6-20× as long as wide, either twisted at base or not. | |
8 Larger mid-stem leaves lanceolate to narrowly elliptic, 7-10 cm long, 10-15 mm wide; leaves not twisted; [KY and s. IN]; [subgenus Pleiactilis, section Unilaterales, subsection Canadensae] | |
7 Rays 4-17 (-24); midstem leaves 5-30 mm wide, 4-12× as long as wide, not twisted at base. | |
12 Mid-stem leaves serrate, the teeth 3-8 (-10) per side, the largest > 1.5 mm long; involucres 1.7-2.5 (-3.0) mm high. | |
14 Stem short pilose to puberulent; leaves usually noticeably less hairy above
than beneath and often darker colored above, with ascending-appressed
hairs on the upper surfaces; [collectively widespread]. | |
15 Upper surface of the leaves moderately to densely pubescent with short, curved to spreading hairs; [western] | |
16 Inflorescence broad; upper stem leaves not reduced in size relative to the mid-stem leaves; [broadly eastern] | |
16 Inflorescence elongated, narrow; upper stem leaves reduced; [southern] |
Key to Solidago, Key F: Key to "dwarf alpine goldenrods" -- dwarf plants with rounded corymbs [subgenus Pleiactila, section Multiradiatae]
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Key to Solidago, Key G: Key to "ptarmicoid goldenrods" -- with corymbs [subgenus Pleiactila, section Ptarmicoidei]
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1 Rays white; leaves linear-lanceolate to linear-oblanceolate, the longer (10-) 15-20× as long as wide; pappus bristles slightly to strongly clavellate-thickened; | |
4 Leaves folded along the midvein (conduplicate, V-shaped in ×-section), with 3-7 veins prominent from the base of the blade; stem leaves strongly recurved away from the stem | |
3 Leaves of the midstem 12-20 mm wide, 2-3.5× as long as wide; leaf surfaces, stems, and peduncles glabrescent to densely pubescent; dry to moist prairies, glades, and savannas]. | |
6 Pubescence of the stems and leaf surfaces finely and densely hispid-strigose, > 50 hairs per square mm; plants usually 3-7 dm tall; flowering arrays compact; inner phyllaries linear, conspicuously strigillose | |
6 Pubescence of the stems and leaf surfaces coarsely hispid, < 50 hairs per square mm; plants 6-15 dm tall; flowering arrays loose, more diffuse; inner phyllaries oblong and with a rounded apex, glabrate or sparsely strigillose |
Key to Solidago, Key H: Key to "bog wand goldenrods" -- with narrowly cylindrical (sometimes broader) inflorescences and sheathing petiole bases [subgenus Pleiactila, section Maritimae]
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1 Leaves somewhat fleshy, the stem leaves reduced but not very markedly so; inflorescence almost always with lower branches strongly recurved with secund heads; [usually of maritime or otherwise saline habitats, rarely in nontidal marshes or swamps]. | |
1 Leaves not fleshy (rarely so in S. stricta of near coastal situations), the stem leaves much reduced relative to the basal; inflorescence showing only relatively weak tendency to recurved branches with secund heads; [inland habitats, except rarely S. stricta]. | |
3 Basal leaves 0.7-8 cm wide; plants short, 4-10 (-15) dm tall, typically fairly stout; [mainly of the Mountains (and the Coastal Plain from e. VA northwards), e. VA, w. NC, nw. SC, ne. GA, and northward]. | |
5 Basal leaves 0.7-2.5 cm wide; stem leaves linear or lanceolate (the lower cauline leaves 0.7-3 cm wide); disc flowers 9-15; [PA and WV (?) northwards] | |
5 Basal leaves 3-8 cm wide; stem leaves oblong-lanceolate (the lower cauline leaves 3-8 cm wide); disc flowers 4-8; [scattered in NC and TN; less sparsely distributed northwards] | |
3 Basal leaves 0.2-2.5 (-5) cm wide; plants short to tall, 3-20 dm tall, typically very slender; [Coastal Plain and lower Piedmont and southward]. | |
6 Basal leaves 0.7-2.5 (-5) cm wide; [collectively more widespread]. | |
7 Mid stem leaves mostly elliptic, oblanceolate, or lanceolate, < 7 × as long as wide; lower floral branches shorter, not remote (to 20 cm and virgate in S. stricta). | |
Key to Solidago, Key I: Key to a diversity of goldenrods with basally disposed leaves and paniculiform inflorescences with heads secund on the branches
[subgenus Nemorales; and subgenus Pleiactila, sections Argutae, Venosae, Maritimae, and Unilaterales)]
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3 Blades of lower leaves ovate to elliptic to oblanceolate, their bases truncate, abruptly tapering, or gradually tapering to petiole; lower leaves including petioles mostly less than 4× as long as wide (sometimes longer in S. brachyphylla with densely puberulent leaf surfaces and stems, and in S. boottii and S. tarda with blades sharply serrate and heads lacking phyllary-like bracts interior to ray florets); [subsection Argutae]. | |
5 Leaves scabrous on the upper surface. | |
6 Involucre (2.5-) avg. 3.9 (-6.5) mm high; basal and lower stem leaves 8-30 cm long, 4-10 cm wide, mostly 2-3× as long as wide; upper stem leaves few, somewhat reduced; disc florets averaging 11.8 per head; [Mountains, Interior Low Plateau, rarely Piedmont, and Coastal Plain only from DE northwards] | |
7 Leaves soft-villous; rays 7-12; flowering May-Jun; [Coastal Plain of e. NC and e. SC] | |
7 Leaves puberulent; rays 0 (-2); flowering Sep-Nov; [SC (NC?) south to FL and AL] | |
9 Plants with slender, stoloniferous rhizomes (in addition to the main, more deeply-seated rhizomes) | |
9 Plants lacking slender, stoloniferous rhizomes. | |
3 Blades of lower leaves oblanceolate to narrowly ovate, gradually tapering to petiole; lower leaves including petioles mostly more than 4× as long as wide (sometimes shorter in S. juncea with at least a few phyllary-like bracts interior to ray florets). | |
16 Stems obviously densely and loosely puberulent; [subsection Nemorales] | |
17 Pappus bristles usually exceeding the length of the ray floret corolla tubes; basal and lower stem leaves narrowly oblanceolate to nearly linear; leaf margins entire or with minute teeth only near the tip; disc corolla lobes (0.6-) 0.8-1.5 mm long; achenes moderately hairy; [mainly western in our region] | |
17 Pappus bristles usually not (or barely) exceeding the length of the ray floret corolla tubes; basal and lower stem leaves oblanceolate to narrowly obovate; leaf margins crenate-serrate through half or more of their length; disc corolla lobes 0.5-0.9 (-1.0) mm long; achenes sparsely hairy; [widespread in our region] | |
16 Stems glabrous or nearly so; [subsection Junceae]. | |
18 Rhizomes thin, elongated, creeping; stem leaves usually 3-nerved; [disjunct from west to glades and barrens] | |
19 Rays 3-7; disc florets 5-9 | |
21 Leaves somewhat fleshy, the stem leaves reduced but not very markedly so; inflorescence almost always with lower branches strongly recurved with secund heads; [usually of maritime or otherwise saline habitats, rarely in nontidal marshes or swamps]. | |
21 Leaves not fleshy (rarely so in S. stricta of near coastal situations), the stem leaves much reduced relative to the basal; inflorescence showing only relatively weak tendency to recurved branches with secund heads; [inland habitats, except rarely S. stricta]. | |
24 Basal leaves 0.7-2.5 cm wide; stem leaves linear or lanceolate (the lower cauline leaves 0.7-3 cm wide); disc flowers 9-15; [PA and WV (?) northwards] | |
24 Basal leaves 3-8 cm wide; stem leaves oblong-lanceolate (the lower cauline leaves 3-8 cm wide); disc flowers 4-8; [scattered in NC and TN; less sparsely distributed northwards] |
Key to Solidago, Key J: Key to " 'false' goldenrods with no ray flowers [subgenus Solidago, section Brintonia]
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Key to Solidago, Key K: Key to "bigheaded goldenrods" [subgenus Pleiactila, section Glomeruliflorae (in part)]
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Key to Solidago, Key L: Key to "sticky goldenrods" -- with basally disposed leaves and elongate, cylindrical inflorescences, mainly of riverscour habitats [subgenus Solidago, section Erectae (in part)]
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1 Leaves, peduncles, and phyllaries slightly glandular; [rocky glades, cliffs, barrens, and river-scoured outcrops, primarily on mafic or calcareous rocks]. | |
2 Cypselas pubescent (even when mature) [e. TN and w. VA northward] | |
3 Lower stem leaves 7-15× as long as wide, (2.5-) 4.6-9.4 (-11.2) cm long, (2-) 3-9 (-17) mm wide, generally obscurely toothed; [rocky, flood-scoured riversides, from e. KY, e. TN, and n. VA northward] | |
2 Cypselas glabrous (even when young); [either rocky, flood-scoured riversides of n. AL, nw. GA, sc. NC , e. TN, and e. KY, or habitat uncertain, Piedmont of SC]. | |
4 Involucres 5-12 mm high; inflorescence with heads more loosely arrayed, with 1-6 heads on a typical 3 cm lateral branch; [n. AL, nw. GA, , e. TN, e. KY, wc. SC] | |
4 Involucres 3-5 mm high; inflorescence with heads more tightly congested, with 6-15 heads on a typical 3 cm lateral branch; [river scour habitats, e. TN and cn. NC]. | |
6 Inflorescence axis and branches densely pubescent with arching hairs; basal leaves lanceolate to ovate, up to 35 mm wide; [known only from the Hiwassee River in e. TN] | |
6 Inflorescence axis and branches glabrous; basal leaves linear-lanceolate, up to 22 mm wide [known only from the Yadkin River in sc. NC] |
Key to Solidago, Key M: Key to "Appalachian squarrose goldenrods" -- with basally disposed leaves, cylindrical inforescensce, and squarrose phyllaries [subgenus Solidago, section Squarrosae]
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Key to Solidago, Key N: Key to "Carolina maritime goldenrods" -- with basally disposed leaves, cylindrical inforescence, and stipitate glandular phyllaries [subgenus Solidago, section Villosicarpae]
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Key to Solidago, Key O: Key to "erect goldenrods" -- with basally disposed leaves and elongate, cylindrical inflorescences (subgenus Solidago, section Erectae]
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1 Phyllaries very narrow, ca. 0.5 (-0.75) mm wide, linear-lanceolate, very gradually tapering to a pointed or minutely rounded tip; [subgenus Solidago, section Erectae, series Puberulae]. | |
2 Stems glabrous proximally up to mid-stem; rays mostly 6-9; inner phyllaries usually striate with 2 prominent secondary veins | |
2 Stems finely hairy throughout with minute strigillose hairs; rays mostly 9-16; inner phyllaries not striate. | |
3 Leaves 20-50 (-60) per stem; midstem leaves usually 4-5 cm long; phyllaries attenuate; [Mountains and Piedmont of GA northward, and Coastal Plain from VA northward] | |
3 Leaves (20-) 50-120 per stem; midstem leaves usually 1-4 cm long; phyllaries acute to acuminate; [Coastal Plain from DE southward] | |
1 Phyllaries broader, (0.75-) 1.0-1.5 mm wide at mid-length, ovate to lanceolate, acute to obtuse or broadly rounded; [subgenus Solidago, section Erectae, series Erectae]. | |
6 Leaves and stems sparsely to densely hairy with long, spreading (to less typically appressed) hairs | |
7 Inflorescence thyrsiform, very slender, usually linear in outline but sometimes with a few widely spaced elongate branches; cypsela bodies 2.2-3.0 mm long; ray flowers often pale yellow; [MA to se. IN, south to GA and MS, mostly avoiding the Coastal Plain southward] | |