Hydrophyllum appendiculatum Michx.

Woollen Breeches

Hydrophyllum appendiculatum plant

Family - Hydrophyllaceae

Stems - To +50cm tall, branching, single from the base, herbaceous, scabrous, hispid, angled from decurrent leaf tissue.

Hydrophyllum appendiculatum stemStem.

Leaves - Alternate, petiolate. Petioles to +17cm long, scabrous, hispidulous. Blades of lower leaves deeply 5-lobed, with a few much smaller lobes on the petiole, green above, silvery-green below, hispidulous, to +12cm long and broad. Lobes acute, shallowly dentate. Teeth mucronate.

Hydrophyllum appendiculatum leaves

Hydrophyllum appendiculatum basalsSpring leaves in-situ.

Inflorescence - Terminal scorpoid panicle to 10cm long. Peduncle hispid. Pedicels to 6-7mm long, hispid.

Hydrophyllum appendiculatum inflorescenceInflorescence.

Flowers - Corolla lilac (or rarely white), 5-lobed. Corolla tube to 4mm long, glabrous. Lobes rounded, 5-6mm long and broad, glabrous externally and internally except for vertical rows of hairs at base of lobe sinuses, fimbrillate on margins. Stamens 5, adnate at base of corolla tube, erect, mostly included. Filaments white-lilac, 8-9mm long, glabrous. Anthers lilac, to 3mm long. Ovary superior, unilocular, with yellow nectariferous ring at the base, conic, 1mm long, with erect white hispid pubescence. Style 7-8mm long, glabrous, white to lilac. Stigma 2-lobed, 1mm long. Calyx 5-lobed and with 5 small projections alternating with the lobes. Projections to 1mm long, spreading. Lobes attenuate, 6mm long, hispid, erect.

Hydrophyllum appendiculatum calyxCalyces.

Hydrophyllum appendiculatum flowerFlowers.

Hydrophyllum appendiculatum appendagesCalyx appendages.

Flowering - April - July.

Habitat - Moist rich woods, slopes, base of bluffs, thickets, wooded valleys.

Origin - Native to U.S.

Other info. - This species can be found throughout Missouri but is apparently absent from the plains region at the southwestern edge of the state. The plant can be locally abundant in the habitats mentioned above. It is distinguished from the two other Missouri members of the genus by having usually lavender-colored flowers borne above the leaves, and most leaves being lobed but not divided to the midvein. Vegetatively the distinction from H. canadense can be difficult. Several subtle leaf characters have been proposed to enable this differentiation but I have not found these to be consistently reliable across populations.
Steyermark mentions two forms based on flower color. Form appendiculatum has a lilac or purplish flower. Form album Steyermark has a white flower and is rare. The specific epithet appendiculatum refers to the tiny triangular appendages which alternate with the main calyx lobes (see photo above).
This is a beautiful species which would do well in a shaded garden setting. It is a biennial and is worthy of cultivation.

Photographs taken at Weston Bend State Park, MO., 5-12-01 (DETenaglia); also at Shaw Nature Reserve, Franklin County, MO, 4-27-2010, at Weldon Spring Conservation Area, St. Charles County, MO, 5-4-2011, at Faust County Park, St. Louis County, MO, 4-4-2012 and 5-2-2016, and at Washington State Park, Washington County, MO, 4-24-2017 (SRTurner).