Lactuca biennis (Tall Blue Lettuce) - photos and description

 

 


Plant just beginning to flower in above photo.


Plant just beginning to flower in above photo.


Plant just beginning to flower in above photo.


Plant with mature inflorescence in above photo, plant over 2 metres tall.


Plant with mature inflorescence in above photo, plant over 2 metres tall



Lower stem leaf in above photo.


Leaf mid stem in above photo


Upper stem leaf in above photo.


First year rosette of leaves

General: Tall, coarse, weedy biennial plants. Stems hollow, we measured a stem to 12 mm diameter. Plants coarsely hairy. Foliage exudes a white sap when broken.

Flowers: Bluish-white in colour, numerous in an elongated, terminal raceme. We measured a mature raceme at 44 cm long. Flowers with ray florets only, no disk florets. We measured flowers at 8 mm diameter and 13 mm long. We observed the flowers opening at 10:30 a.m., and closing at 1:30 p.m.

Leaves: Leaves are alternate, lower stem and mid stem are large, deeply lobed with sharp-toothed margins. We measured a lower leaf at 25 cm long by 12 cm wide. Leaves reduced upwards. Lower leaves clasp the stem, upper leaves are sessile. Top most leaves often without lobes and only with a few teeth. The upper stem leaf highlighted in the photo above was measured at 11 cm long by 13 mm wide.

Height: Height listed in Budd's Flora to 2.5 m tall, we measured plants to 2.28 m tall.

Habitat: Lakeshores and moist, rich woods.

Abundance: Rare, ranked as an S3 by the Saskatchewan Conservation Data Centre.

Origin: Native.

When and where photographed: Photos taken June 28th, July 19th, July 21st, edge of forest trail, Moose Mountain provincial park, about 200 km southeast of Regina, SK, and, July 26th, bushy meadow on edge of lake, Duck Mountain provincial park, about 300 km northeast of our home in Regina, SK.