Published In:
Synopsis Plantarum in Flora Gallica Descriptarum 255. 1806. (30 Jun 1806) ( Syn. Pl. Fl. Gall.)
(Last Modified On 8/11/2017)
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Acceptance
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Accepted
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(Last Modified On 8/10/2009)
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4. Tribe Cichorieae Lam. & DC.
(Tribe Lactuceae
Cass.)
Plants annual,
biennial, or perennial herbs (rarely woody elsewhere), the sap usually milky
(white or colored). Stems not spiny or prickly. Leaves alternate and/or in a
basal rosette, sessile or petiolate, the base sometimes somewhat sheathing the
stem, occasionally spiny or prickly. Leaf blades entire to deeply pinnately
lobed, the venation pinnate (or the veins too faint to observe), mostly with 1
main vein (the leaves usually grasslike in Tragopogon with few to
several parallel veins). Inflorescences mostly terminal; panicles, clusters of
heads, or occasionally racemes, or the heads solitary (sometimes appearing as
axillary clusters or terminal and spikelike in Cichorium). Heads
ligulate. Involucre most commonly of a longer, inner series of uniform bracts
(these sometimes fused laterally, at least toward the base) and 1 or more shorter
series of outer bracts, less commonly with 2 or more overlapping series of more
or less similar bracts, the bracts not spiny or tuberculate, often becoming
reflexed as or after the fruits mature. Receptacle flat or nearly so, naked or
less commonly the florets subtended by chaffy bracts or minute hairs. Ligulate
florets perfect, the corollas 5-toothed at the tip, variously colored. Disc and
ray florets absent. Pappus usually of numerous capillary bristles (these
sometimes plumose), occasionally with an outer, shorter whorl of bristles,
hairs, or scales, less commonly only of scales or absent, when present
persistent at fruiting (except sometimes in Picris). Stamens with the
filaments not fused together, the anthers fused into a tube, each tip usually with
a short appendage, each base with a pair of auricles or slender lobes. Style
branches short or long and usually not or only slightly flattened, each with a
stigmatic band along the inner surface, the sterile tip short and rounded or
less commonly truncate, the outer surface and tip often with dense, minute
hairs. Fruits usually all similar, often flattened or angled in cross-section,
variously shaped, sometimes ribbed, not winged, sometimes developing a short
and stout or elongate and slender beak at maturity. About 120 genera, about
3,200 species, worldwide.
The Cichorieae
are perhaps the most easily recognized tribe of Asteraceae in Missouri, because
of their ligulate heads and milky sap. Dried specimens collected in bud
occasionally may be confused with Senecioneae because of similarities in
involucral bracts and pappus.
The tribe is
economically important primarily for the large number of weedy species,
although many of these are restricted to highly disturbed areas. Most of the
plants are edible, at least when young, and some genera are (or formerly were)
of commercial importance for use in food and beverages, such as Cichorium
(chicory, endive), Lactuca (lettuce), and Tragopogon (salsify).
Relatively few species are cultivated as ornamentals.
Plants of this
tribe tend to be quite variable in leaf morphology, so the key to genera below
emphasizes pappus characters, which are usually observable (sometimes only with
magnification) on fertile specimens, regardless of whether buds, flowers, or
fruits are present. In general, Hypochaeris, Leontodon, Nothocalais,
Taraxacum, and some species of Hieracium and Krigia have
leaves only in a basal rosette (excluding any bracts in the inflorescence),
whereas the other genera have stems noticeably leafy above the base. However,
young or depauperate plants of species otherwise in the latter group rarely may
appear to have only basal leaves, and Lygodesmia may appear nearly
leafless at maturity. In Missouri, prickly leaves may be found in some species
of Lactuca, Picris, and Sonchus. The key to genera requires both
flowers and fruits for a few of the more difficult genera. Fortunately, these
groups tend to have long periods of bloom with heads at different stages
present on the same plant. Additionally, flowering heads will often continue to
develop fruits during the pressing process or if an inflorescence branch is
placed in an envelope and allowed to dry.
Missouri
botanists should be aware of the following potential future addition to the
state’s flora, which does not key well in the key to genera below. Chondrilla
juncea L. (rush skeletonweed, hogbite) is a weed of crop fields, pastures,
and natural grasslands that is listed as a noxious weed in several states to
the west and north of Missouri. It has also been spreading sporadically in a
number of eastern states and may eventually be found in Missouri. This Eurasian
perennial can grow to 1.5 m tall. The stems have numerous ascending branches
from a usually unbranched basal portion. Although a rosette of pinnately lobed leaves
is produced, this usually withers by flowering time and the main stem leaves
are inconspicuous, linear, and unlobed. The slender heads have an involucre of
5–9 main bracts 9–12 mm long surrounding 7–15 florets with yellow corollas. The
fruits are about 3 mm long, several-nerved, and have a whorl of 3 or 4 tiny
scales at the expanded tip of the long, slender beak in addition to the
numerous capillary bristles.
1
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1. Pappus absent or of scales (these sometimes short and inconspicuous in Krigia), if of scales then sometimes also with bristles (Leontodon and Nothocalais, which have a pappus of mixed bristles and long, slender [broad-based] scales, should be keyed under this lead)
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2
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2. Pappus a mixture of bristles and scales, the scales sometimes slender and awnlike from an expanded base or short and inconspicuous; plants usually with the leaves all basal (the inflorescence sometimes with a leaflike basal bract in Krigia); corollas yellow or orange
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3
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3. Pappus mostly of long, slender scales, these mostly bristlelike and plumose from a flattened, expanded base, usually associated with a few somewhat shorter, merely barbed, capillary bristles (note that the outermost florets of the head have a different pappus that is composed of a short, scaly crown, without any longer scales or bristles); some of the hairs, especially on the leaves and involucres, minutely forked at the tip ... 41. LEONTODON
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Leontodon
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4
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3. Pappus with as many bristles as scales or more bristles than scales, the bristles smooth or minutely barbed, not plumose; hairs all simple or the plants glabrous
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5
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4. Involucre 4–14 mm long; pappus of 5 to numerous bristles but only 5 or (8–)10 scales ... 38. KRIGIA
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Krigia
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6
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4. Involucre 17–25 mm long; pappus of numerous bristles intermixed with usually numerous scales ... 43. NOTHOCALAIS
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Nothocalais
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7
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2. Pappus absent or only of scales; plants usually with at least a few leaves above the base along the stem (except on Leontodon) corollas yellow or blue (rarely white or pink)
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8
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5. Pappus present, of minute or slender scales; corollas yellow or blue (rarely white or pink)
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9
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6. Pappus of minute scales; corollas blue (rarely white or pink); leaves usually basal and alternate along the stems (the stem leaves often much smaller than the basal ones) ... 33. CICHORIUM
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Cichorium
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10
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6. Pappus of the outermost florets a short, scaly crown, without any longer scales, that of the other florets of slender, awnlike scales, these bristlelike above an expanded, flattened base; corollas yellow; leaves all basal ... 41. LEONTODON
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Leontodon
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11
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5. Pappus absent; corollas yellow
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12
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7. Involucre with 1 or 2 series of 4–7(–9) ascending bracts, these all similar in size and shape (no outer, shorter bracts present); fruits 1.4–1.7 mm long ... 38. KRIGIA
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Krigia
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13
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7. Involucre with an inner series of usually 8 longer, ascending bracts and an irregular outer series of minute, spreading bracts; fruits 3–5 mm long ... 40. LAPSANA
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Lapsana
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14
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1. Pappus only of bristles, these often minutely barbed or plumose (Pyrrhopappus, which has a ring of minute, reflexed hairs attached immediately below the pappus bristles, should be keyed under this lead)
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15
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8. Pappus with some or all of the bristles plumose
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16
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9. Leaves all basal
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17
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10. Receptacle with long, slender, chaffy bracts subtending the florets; leaves pubescent with unbranched hairs ... 37. HYPOCHAERIS
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Hypochaeris
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18
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10. Receptacle naked (the florets sunken into minute pits); leaves with at least some of the hairs minutely forked at the tip ... 41. LEONTODON
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Leontodon
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19
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9. Leaves basal and alternate, the basal leaves sometimes withered by flowering time
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20
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11. Leaves mostly grasslike, with few to several main veins, glabrous or with small patches of inconspicuous cobwebby hairs toward the base when young ... 49. TRAGOPOGON
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Tragopogon
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21
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11. Leaves not grasslike, with 1 main vein and sometimes also a faint network of anastomosing secondary veins, pubescent with some of the hairs barbed at the tip with 2–5 minute, spreading to recurved branches from a knoblike tip
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22
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12. Outer involucral bracts 3–5, in 1 series, all similar, slightly shorter than to slightly longer than the inner series, ovate to broadly ovate; fruits with a slender beak 1–2 times as long as the body ... 35. HELMINTHOTHECA
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Helminthotheca
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23
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12. Outer involucral bracts 7–13 in 2 or 3 progressively longer series ranging from much shorter than to more than 1/2 as long as the inner series, narrowly lanceolate to narrowly oblong-lanceolate; fruits sometimes slightly tapered toward the tip but not beaked ... 44. PICRIS
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Picris
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24
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8. Pappus with all of the bristles smooth or with minute, ascending barbs
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25
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13. Leaves all basal
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26
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14. Leaves deeply and irregularly lobed and toothed; fruits long-beaked at maturity ... 48. TARAXACUM
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Taraxacum
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27
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14. Leaves not lobed, entire or less commonly sometimes slightly wavy or with a few inconspicuous teeth; fruits not beaked at maturity
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28
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15. Inflorescence a panicle, raceme, or cluster of flowers; leaf surfaces and margins with relatively long, spreading hairs having a bulbous or slightly expanded base, often also with minute, stellate hairs (visible only with magnification) ... 36. HIERACIUM
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Hieracium
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29
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15. Inflorescence consisting of a solitary long-stalked head; leaves with the surfaces glabrous or sparsely and inconspicuously hairy with short, curled hairs, the margins with a dense fringe of very short, curly hairs ... 43. NOTHOCALAIS
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Nothocalais
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30
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13. Leaves basal and alternate, the basal leaves sometimes withered by flowering time (Lygodesmia, with the stem leaves linear to very narrowly triangular, often scalelike and mostly withered by flowering time, should be keyed under this lead)
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31
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16. Fruits with a dense ring of minute, reflexed hairs attached immediately below the pappus bristles; involucral bracts with an abrupt, small, crestlike thickening just below the tip, because of this often appearing irregular, notched, or jointed near the tip ... 46. PYRRHOPAPPUS
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Pyrrhopappus
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32
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16. Fruits without a ring of hairs just below the pappus; involucral bracts not thickened at or near the tip, not appearing notched or jointed
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33
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17. Leaves not lobed, the margins entire or less commonly slightly wavy or with a few shallow, inconspicuous teeth
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34
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18. Stem leaves linear to very narrowly triangular, inconspicuous and often scalelike and mostly withering or shed by flowering time; ligulate florets 4–6 per head ... 42. LYGODESMIA
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Lygodesmia
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35
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18. Stem leaves variously shaped but not scalelike or withered by flowering time; ligulate florets 8 to numerous per head (except for Prenanthes altissima, with only 5 or 6 florets)
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36
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19. Leaves with relatively long, spreading hairs having a bulbous or slightly expanded base (often also with minute, stellate hairs visible only with magnification) ... 36. HIERACIUM
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Hieracium
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37
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19. Leaves glabrous or with sparse to moderate, short, curled, unbranched hairs and/or stouter, spreading hairs on the undersurface along the midvein, these often tapered from a slightly broadened, somewhat flattened, nonbulbous base and sometimes grading into prickles (minute, stellate hairs sometimes also present in Prenanthes)
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38
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20. Pappus bristles white or nearly so; leaves mostly 4–20 times as long as wide or, if 2–3 times as long as wide (in L. sativa), then the surface strongly and irregularly crisped or curled and the blade sessile or nearly so; mature fruits flattened ... 39. LACTUCA
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Lactuca
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39
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20. Pappus bristles straw-colored to tan, orangish brown, or reddish brown; leaves mostly 1–3 times as long as wide or, if 3–5 times as long as wide, then the blade tapered abruptly to a winged petiole; mature fruits more or less circular in cross-section or 4- or 5-angled, not flattened ... 45. PRENANTHES
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Prenanthes
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40
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17. At least the largest leaves deeply lobed and/or coarsely toothed
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41
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21. Pappus bristles straw-colored to tan, orangish brown, or reddish brown; corollas white, pink, purple, or cream-colored, rarely greenish yellow ... 45. PRENANTHES
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Prenanthes
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42
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21. Pappus bristles white; corollas lemon yellow to orangish yellow (purplish blue to blue in some Lactuca species)
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43
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22. Mature fruits not flattened, more or less circular or (4)5–10-angled in cross-section ... 34. CREPIS
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Crepis
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44
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22. Mature fruits flattened (also with 1 or more nerves on each face)
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45
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23. Mature fruits with a long beak (except in L. floridana, which has blue corollas), the pappus attached at an expanded, disclike tip (this more or less visible even at flowering); ligulate florets 9–55 per head; corollas yellow or purplish blue to blue ... 39. LACTUCA
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Lactuca
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46
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23. Mature fruits not beaked, the pappus attached at an unexpanded, unmodified tip; ligulate florets 80–250 or more per head; corollas yellow ... 47. SONCHUS
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Sonchus
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