Rumex stenophyllus (Narrow-Leaved Field Dock) - photos and description
Valves in threes, valves coarsely toothed, one grain/tubercle per
valve, grains 1/2 to 1/3 as long as valve.
Pedicels jointed.
July 26th, plant is drying out, turning rust red in colour
General: Stout, erect, usually single-stemmed perennial, inflorescence is tall and narrow. Stems are red.
Flowers: Flowers small, greenish (not shown).
Fruit: Fruit is a three-sided achene, each side triangular in shape and known as a valve. The valves are coarsely toothed, each with a grain/tubercle growing on their surface, the grain 1/2 to 1/3 the length of the valve. We measured a valve at 4 mm long by 3 mm wide. The pedicels each have a small joint below the middle.
Leaves: Leaves are alternate, linear to lanceolate, wavy-margined. The blade of the leaf highlighted in the photo above was 70 mm long by 36 mm wide (pressed flat).
Height: Height listed in Budd's Flora to 200 cm. We measured plants to 70 cm tall.
Habitat: Wet meadows, shores, ditches, stream banks, and disturbed places, often where saline.
Abundance: Common.
Origin: Introduced.
How to identify this species of Rumex: Pedicels jointed, 3 grains per fruit (each valve with a grain), valves with coarse teeth, leaves wavy-margined.
Similar species: This plant might be confused with Rumex crispus which also has wavy-margined leaves, and jointed pedicels. However, that plant has valves with entire to lightly erose margins and has 1 tubercle noticeably larger than the other two, whereas R. stenophyllus has valves with coarse teeth and tubercles more or less equal in size.
This plant might be confused with Rumex pseudonatronatus which also has wavy-margined leaves, and jointed pedicels. However, that plant has only 1 weakly developed tubercle per fruit and valves with entire margins, whereas Rumex stenophyllus has three tubercles per fruit and valves with coarse teeth.
When and where photographed: Photos taken July 22nd, shore of saline lake, prairie, about 200 km west of our home in Regina, SK.