E-Flora BC: Electronic Atlas of the Flora of British Columbia

Lactuca biennis (Moench) Fernald
tall blue lettuce
Asteraceae (Aster family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #11531)

E-Flora BC Static Map
Distribution of Lactuca biennis
Click here to view our NEW interactive map and legend
Details about map content are available here
Click on the map dots to view record details.

Species Information

Click on the image below to view an expanded illustration for this species.



General:
Annual or biennial herb from a taproot; stems erect, branched above, usually solitary, glabrous, exuding milky juice when broken, 0.6-2.5 m tall.
Leaves:
Basal leaves lacking; stem leaves alternate, pinnately cut or toothed, 10-40 cm long, 4-20 cm wide, sometimes hairy along the main veins, the upper ones with ear-like flanges at the base, clasping.
Flowers:
Heads with strap-shaped flowers, numerous in a narrow, elongate inflorescence; involucres 9-14 mm tall; involucral bracts lanceolate, graduated, often purplish at the tip, glabrous; ray flowers bluish to white, sometimes yellow, 13-34.
Fruits:
Achenes thin-edged, prominently nerved, beakless or shortly stout-beaked less than 1/2 the length of the body, 4-5.5 mm long; pappus brownish.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist ditches, meadows and forest openings in the lowland, steppe and montane zones; frequent throughout most of BC; E to NF and S to NC, CO and CA.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Lactuca biennis

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class

Minimum

Average

Maximum

Elevation (metres) 44 244 555
Slope Gradient (%) 0 10 76
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
45 220 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
2 3 4
Modal Nutrient Regime
Class
C
Number of field plots
 species was recorded in:
30
Modal BEC Zone Class
CWH
All BEC Zones (# of stations/zone) species was recorded in: CWH(26), SBS(1)

Climate

The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Lactuca spicata auct. non (Lam.) Hitchc.
Lactuca spicata var. integrifolia (Torr. & A. Gray) Britton
Mulgedium spicatum auct. non (Lam.) Small
Mulgedium spicatum var. integrifolium (Torr. & A. Gray) Small

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References