Taraxacum trigonolobum

Dahlstedt

Ark. Bot. 20A(1): 8, fig. 5. 1926.

Treatment appears in FNA Volume 19. Treatment on page 249. Mentioned on page 242, 248.
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Plants 8–41 (–56.5 in fruit) cm; taproots seldom branched. Stems 1–5, ascending to erect, purplish, glabrous or glabrescent proximally, ± densely villous distally. Leaves fewer than 10, horizontal or patent to ± erect; petioles widely winged; blades oblanceolate-obovate (largest in distal 1/5) to oblanceolate (often runcinate, particularly early leaves), (3.5–) 6–29.5 × (1.3–) 2.1–5.5 cm, bases cuneate to attenuate, margins sometimes lobed proximally or ± regularly and deeply, usually ± strongly toothed proximally (less so on distal 1/2–1/5), lobes retrorse to straight or antrorse, triangular to deltate, ± acuminate, teeth mostly proximal, rarely on distal 1/4–1/5 or terminal lobes, small to coarse, irregular (1–5 on lobes), apices rounded or truncate to obtuse, rarely acute, apiculate, faces glabrous or glabrate (very sparsely pilose, mainly on midveins). Calyculi 14–20, appressed (to spreading), often pale green, ovate to elliptic-ovate bractlets in 2–3 series, 5–8 × 2.8–4.5 mm, margins narrowly white, scarious (occasionally outer ± ciliate), apices acuminate to caudate, some strongly horned, tips dark-scarious. Involucres dark green, ± glaucous, broadly campanulate, 15–20 mm. Phyllaries 14–20 in 2 series, lanceolate, 2.1–2.8 mm wide, margins ± narrowly scarious (wider proximally, or not in outer series), apices strongly horned, tips purplish with dark center, scarious, ± erose. Florets 120–150; corollas yellow, outer grayish-purplish striped abaxially, 19–25 × 1.3–2.3 mm. Cypselae brown to reddish-brown, bodies oblanceoloid, 3–3.5 mm, cones conic, 0.8–1 mm, beaks slender, 7.5–10 mm, ribs 4–5 prominent (to 15 fine), faces proximally smooth (faintly tuberculate), muricate in distal 1/4; pappi yellowish or cream to white, 7–8 mm.


Phenology: Flowering summer.
Habitat: Herbaceous vegetation, lakeshores, moist banks, alluvial shores, moist meadows, moist heaths, grassy cliff tops
Elevation: 0–600 m

Distribution

V19-326-distribution-map.gif

Alaska, Russian Far East (Kamchatka)

Discussion

Taraxacum trigonolobum is known only from the Aleutian Islands and islands of the Bering Sea, on the American side. It is probably the taxonomically weakest entity that I am recognizing in this complex, but its distribution and leaf morphology, among other attributes, are distinctive enough for recognition at the present time.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Taraxacum trigonolobum"
horned;horned;acuminate;caudate +
ovate +  and lanceolate +
paniculiform +  and corymbiform +
indeterminate +  and determinate +
Luc Brouillet +
Dahlstedt +
cuneate +  and attenuate +
slender +
0.75 cm7.5 mm <br />0.0075 m <br /> (1 cm10 mm <br />0.01 m <br />) +
compound +  and simple +
3.5 cm35 mm <br />0.035 m <br /> (6 cm60 mm <br />0.06 m <br />) +
1.3 cm13 mm <br />0.013 m <br /> (2.1 cm21 mm <br />0.021 m <br />) +
6 cm60 mm <br />0.06 m <br /> (29.5 cm295 mm <br />0.295 m <br />) +
oblanceolate-obovate;oblanceolate +
2.1 cm21 mm <br />0.021 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
tuberculate +, rugose +, muricate +  and smooth +
oblanceoloid +
0.3 cm3 mm <br />0.003 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
broadly ovate;lanceolate +
0.28 cm2.8 mm <br />0.0028 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
filiform +
white +  and cream-colored or yellowish +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
zygomorphic +, actinomorphic +  and (3-)5-merous +
grayish-purplish striped +  and yellow +
1.9 cm19 mm <br />0.019 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
brown +  and reddish-brown +
tapered +, beaked +, flattened +, obcompressed +, compressed +, prismatic +, fusiform +, ellipsoid +, columnar +  and clavate +
Alaska +  and Russian Far East (Kamchatka) +
0–600 m +
glabrate +  and glabrous +
muricate +
winged +  and beaked +
dispersed +
Herbaceous vegetation, lakeshores, moist banks, alluvial shores, moist meadows, moist heaths, grassy cliff tops +
indeterminate +
each +  and sessile +
0.8 cm8 mm <br />0.008 m <br /> (4 cm40 mm <br />0.04 m <br />) +
campanulate +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
sessile +  and petiolate +
patent +  and more or less erect +
0 (?) +  and 10 (?) +
straight +
antrorse;retrorse +
acuminate +, triangular +  and deltate +
toothed +  and lobed +
2-carpellate +
cream +  and white +
persistent +
0.7 cm7 mm <br />0.007 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
Flowering summer. +
closing +  and later +
distinct +  and coherent +
14 +  and 20 +
subequal +  and unequal +
0.21 cm2.1 mm <br />0.0021 m <br /> (0.28 cm2.8 mm <br />0.0028 m <br />) +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
prominent +
4 +  and 5 +
exalbuminous +
1 (?) +  and 10 (?) +
ascending +  and erect +
villous +, glabrescent +  and glabrous +
1 +  and 5 +
scapiform +
appendaged +  and truncate +
papillate +
Undefined tribe Lactuceae +
Taraxacum trigonolobum +
Taraxacum +
species +
scarious +  and dark-scarious +
with branched caudices +  and taprooted +
10 cm100 mm <br />0.1 m <br /> (30 cm300 mm <br />0.3 m <br />) +
30 cm300 mm <br />0.3 m <br /> (400 cm4,000 mm <br />4 m <br />) +