Dirca decipiens Floden

Upland Leatherwood


CC =
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MOC = 2

© SRTurner

Family - Thymelaeaceae

Habit - Shrub to 2 m

Stems - Multiple from base. Twigs 3-5 mm wide, yellowish brown to gray-brown. First year growth densely pubescent with short, appressed, white hairs.

Dirca_decipiens_twig1.jpg Young twig.

© SRTurner

Dirca_decipiens_twig2.jpg Older twigs.

© SRTurner

Leaves - Alternate, simple, short-petiolate to nearly sessile. Petioles 1-4 mm long, densely appressed-hairy. Leaf blades obovate to oblong, 2-9 cm long, rounded or broadly angled to a bluntly pointed tip, rounded or angled at the base, the margins usually relatively densely and finely hairy (mostly 11-18 hairs per mm), glabrate on the upper surface, densely pubsecent abaxially.

Dirca_decipiens_leaves.jpg Stem and leaves.

© SRTurner

Dirca_decipiens_leaf2.jpg Leaf abaxial.

© SRTurner

Dirca_decipiens_leaf2a.jpg Leaf abaxial surface.

The dense pubescence is a key attribute differentiating this species from the more common D. palustris.

© SRTurner

Inflorescences - Small clusters, typically with 2-4 flowers, appearing before the new leaves. Individual flowers sessile or nearly so, the minute stalks, if present, not elongating at fruiting. Persistent bracts 6-15 mm at flowering, continuing to enlarge to 40 mm or more as the fruits develop, oblong-obovate, the upper surface usually sparsely hairy along the veins, the undersurface woolly with dense, white to gray or tan hairs.

Dirca_decipiens_inflorescences.jpg Inflorescences.

© SRTurner

Dirca_decipiens_inflorescence.jpg Inflorescence.

© SRTurner

Dirca_decipiens_bract.jpg Bract.

© SRTurner

Flowers - Peduncle absent or nearly so. Calyces 7-11 mm long (including the hypanthium), with 4 distinct but irregular lobes 1-3 mm, the margin also irregular and/or minutely scalloped. Corollas absent. Stamens 8, exserted, the filaments of 2 lengths, attached in a ring to the inner surface of the calyx above the hypanthium portion, the anthers small, attached basally, yellow. Pistil 1 per flower, appearing composed of 1 carpel, the superior ovary sometimes with a minute, irregularly lobed nectar disc at the base. Style 1, slender, exserted and extending beyond the anthers, not persistent at fruiting, the stigma 1, minute, capitate. Ovules 1, the placentation more or less basal.

Dirca_decipiens_flowers1.jpg Flowers.

© SRTurner

Dirca_decipiens_flowers2.jpg Flowers.

© SRTurner

Dirca_decipiens_flowers3.jpg Flowers.

Note the absence of any discernable flower stalks.

© SRTurner

Fruits - Drupes 7-9 mm long, ovoid to ellipsoid-ovoid or slightly pearshaped, with an inconspicuous tuft of short hairs at the tip.

Dirca_decipiens_fruits.jpg Fruits.

These are completely sessile to the twig.

© SRTurner

Flowering - March - April.

Habitat - Upland wooded slopes and bluffs above rivers, often associated with oak and juniper.

Origin - Native to the U.S.

Lookalikes - Dirca palustris.

Other info. - This species of leatherwood was first recognized as distinct from D. palustris by Aaron Floden in the early 2000s. It is believed to be quite rare, thus far having been identified in only six counties in Missouri, Arkansas, and Kansas. Due to its rarity, the plant is considered critically imperiled.

Although this species closely resembles the far more common Dirca palustris, differentiation is not difficult with close attention to the proper details. First, any Dirca plants growing in upland habitats should be examined closely, as D. palustris is usually found in moist bottomlands. The flowers of D. decipiens are essentially sessile, whereas those of D. palustris are on short stalks. (The flowers bear a long tubular hypanthium, just behind the expanded portion of the calyx, which should not be mistaken for a stalk.) Stalks can be difficult to discern on very early flowering material, but become very evident at the fruiting stage. The dense bract hairiness in D. decipiens is light-colored, whereas in D. palustris it is brown. The flowers of D. decipiens also tend to be larger. These key characters are all clearly illustrated via the images on the corresponding species pages of this website.

Photographs taken at in Gasconade County, MO, 4-8-2021, and in Bel-Nor, St. Louis, MO, 4-2-2023 and 5-2-2023 (SRTurner).