[The Genus Thelypodium East of the Cascade Mts.]

Arrow-leaved Thelypody

Thelypodium eucosum

The photo above shows the spidery flower of arrow-leaf thelypody as photographed in the Malheur NF.............June 22, 2003. Note the developing silique emerging from the flower.


The photo at right shows the siliques of arrow-leaf thelypody as photographed in the Malheur NF.............June 22, 2003. Note the spreading pedicels and the upturned siliques with the covering slightly constricted between seeds.
Characteristics:

Arrow-leaved thelypody is a perennial wildflower with erect stems either freely branched below or only above. The stems arise 30-60 cm and the herbage is mostly glabrous and somewhat glaucous. The basal leaves are sessile or short-petiolate, lanceolate to oblanceolate with entire to wavy margins and blades from 2-5 cm long. The numerous stem leaves are oblong-lanceolate to lanceolate in shape and measure 2-7 cm long. The margins are entire and the bases are heart-shaped and often clasping.

The racemes may resemble a corymb early in flowering, but they soon elongate into evident racemes. The pedicels are widely spreading, measuring 3-5 mm long and the bright lilac-purple sepals are narrow and widely spreading, measuring 4-5 mm long. The narrowly spatulate petals are likewise a bright lilac-purple color and measure 6-11 mm long. The stamens slightly exceed the petals. The filaments are very slender and the anthers are about 2 mm long. The fruits are slender siliques which are 3-4.5 cm long and strongly curved upwards near the base. The covering of the silique is slightly constricted between the seeds (Barely noticeable in the photo at right.).


Habitat:

Arrow-leaved thelypody is found in dry, open ponderosa pine forests.


Range:

Arrow-leaved thelypody is found in the Blue Mts. of Grant, Baker and Wheeler counties in Oregon, and in Idaho.


The photo above shows the basal leaves of arrow-leaved thelypody.

The photo above shows the raceme of arrow-leaved thelypody.

The photo above shows the basal leaves and lower stem of arrow-leaf thelypody.

The photo above shows an example of an entire plant of arrow-leaved thelypody.

Paul Slichter