Lactuca biennis

(Moench) Fernald

Rhodora 42: 300. 1940.

IllustratedEndemic
Basionym: Sonchus biennis Moench Methodus, 545. 1794
Treatment appears in FNA Volume 19. Treatment on page 261. Mentioned on page 260.

Annuals or biennials, (15–) 75–200 (–300+) cm. Leaves on proximal 2/3–3/4 of each stem; blades of undivided cauline leaves ovate to lanceolate, margins entire or denticulate, midribs sometimes sparsely piloso-setose. Heads in paniculiform arrays. Involucres 7–12+ mm. Phyllaries usually reflexed in fruit. Florets (15–) 20–30 (–50+); corollas bluish or whitish, sometimes yellowish, seldom deliquescent. Cypselae: bodies brown (often mottled), ± compressed-ellipsoid, 4–5+ mm, beaks ± stout, 0.1–0.5+ mm, faces (4–) 5–6-nerved; pappi ± fuscous, 4–6+ mm. 2n = 34.


Phenology: Flowering Jul–Oct.
Habitat: Swamps, stream banks, woods
Elevation: 900–1500 m

Distribution

V19-348-distribution-map.gif

St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr., N.S., Ont., P.E.I., Que., Sask., Yukon, Alaska, Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mont., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Tenn., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.

Discussion

The type of Lactuca terrae-novae Fernald is probably conspecific with that of L. biennis. The type of L. biennis may be conspecific with that of L. floridana.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Lactuca biennis"
obtuse;acute +
scarious +
ovate +  and lanceolate +
paniculiform +
indeterminate +  and determinate +
John L. Strother +
(Moench) Fernald +
decurrent +
Sonchus biennis +
filiform +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
compound +  and simple +
lanceolate;oblanceolate linear or filiform +
tuberculate +, rugose +, muricate +  and smooth +
compressed-ellipsoid +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
deltate;lanceolate +
filiform +
simple +, barbellulate +  and nearly smooth +
zygomorphic +, actinomorphic +  and (3-)5-merous +
yellowish +, whitish +  and bluish +
fuscous +  and white +
subtending +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
purplish +  and blackish +
tapered +, beaked +, flattened +, obcompressed +, compressed +, prismatic +, fusiform +, ellipsoid +, columnar +  and clavate +
St. Pierre and Miquelon +, Alta. +, B.C. +, Man. +, N.B. +, Nfld. and Labr. +, N.S. +, Ont. +, P.E.I. +, Que. +, Sask. +, Yukon +, Alaska +, Calif. +, Colo. +, Conn. +, Del. +, D.C. +, Idaho +, Ill. +, Ind. +, Iowa +, Ky. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Mont. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Oreg. +, Pa. +, R.I. +, S.Dak. +, Tenn. +, Utah +, Vt. +, Va. +, Wash. +, W.Va. +, Wis. +  and Wyo. +
900–1500 m +
(4-)5-6-nerved +
rugulose +
winged +  and beaked +
dispersed +
Swamps, stream banks, woods +
in corymbiform to paniculiform arrays +  and singly +
indeterminate +
each +  and sessile +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
campanulate;cylindric +
0.7 cm7 mm <br />0.007 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
petiolate +  and sessile +
cauline +  and basal +
denticulate +  and entire +
piloso-setose +
2-carpellate +
persistent +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Flowering Jul–Oct. +
connate +  and distinct +
5 +  and 13 +
flat;convex +
1 +  and 9 +
exalbuminous +
Illustrated +  and Endemic +
hairy +  and glabrous +
appendaged +  and truncate +
papillate +
Undefined tribe Lactuceae +
Lactuca biennis +
species +
200 cm2,000 mm <br />2 m <br /> (300 cm3,000 mm <br />3 m <br />) +
biennial +  and annual +
75 cm750 mm <br />0.75 m <br /> (200 cm2,000 mm <br />2 m <br />) +
shrub +  and subshrub +