Draba aprica Beadle

Open-Ground Whitlow Grass


CC = 10
CW = 5
MOC = 9

© SRTurner

Family - Brassicaceae

Habit - Annual forb.

Stem - Ascending to erect, usually single and unbranched, to 40 cm, hairy.

Draba_aprica_stem.jpg Stem and leaves.

© SRTurner

Leaves - Basal and alternate, more or less evenly distributed along the stems, 0.4-2.0 cm long, sessile or the basal leaves often short-petiolate, linear to obovate or broadly elliptic, the margins entire or less commonly few-toothed, hairy on both surfaces.

Draba_aprica_basals.jpg Basal leaves.

© SRTurner

Draba_aprica_leaf1.jpg Stem leaf, adaxial.

© SRTurner

Draba_aprica_leaf2.jpg Stem leaf, abaxial.

© SRTurner

Inflorescences - Axillary and terminal panicles, the branches often short and densely flowered. Flowers dense, those of the lateral branches often appearing fascicled.

Draba_aprica_inflorescence2.jpg Axillary fasciles (fruiting stage).

© SRTurner

Draba_aprica_inflorescence1.jpg Inflorescence.

© SRTurner

Flowers - Sepals 0.8-1.5 mm long. Petals 2-3 mm long (sometimes absent), white, rounded or very slightly indented at the tip. Styles absent or to 0.2 mm long.

Fruits - Fruits 3-6 mm long, linear to narrowly elliptic in outline, hairy. Seeds 4-8 per fruit.

Draba_aprica_fruits.jpg Fruits.

© SRTurner

Flowering - April - May.

Habitat - Streambanks, forest openings, rock outcrops and ledges of shut-ins, glades, roadsides. On both calcareous and acidic substrates.

Origin - Native to the U.S.

Lookalikes - Other species of Draba, particularly D. brachycarpa.

Other info. - This small and inconspicuous species is found in Missouri in only a few counties in the St. Francois Mountains region. Its larger distribution is limited to only 6 states within the southeastern quadrant of the continental U.S., and it considered rare everywhere outside of Missouri. Clues to its identity as a Draba include its small stature, branched hairs on the herbage, white flowers, and football-like fruit shape which falls between silique (very long and slender) and silicle (nearly round in profile). D. aprica is distinguished from other species of Draba by its leafy stems and hairy fruits.

This is the least common species of Draba in Missouri. Interestingly, Yatskievych remarks that it tends to colonize the gravel piles left by graders at the edges of unpaved roads. It sometimes grows in mixed populations with D. brachycarpa, but the two apparently do not cross. The plant has been considered a variety of D. brachycarpa (D. brachycarpa Nutt. ex Torr. & A. Gray var. fastigiata Nutt. ex Torr. & A. Gray). Another common name for this species is "granite whitlow grass."

Photographs taken at Silver Mines Recreation Area, Madison County, MO, 5-12-2015, and at Millstream Gardens Conservation Area, Madison County, MO, 4-28-2020 (SRTurner).