Dirca

Shrubs, deciduous, to 3 m. Stems erect, branched, appearing jointed, woody, sericeous or or (3–)4-lobed; petals (absent in D. palustris), included, minute, forming ring at base of staminal filaments; stamens 8, exserted, inserted within calyx; style exserted, elongate; stigma punctiform. Fruits drupaceous, yellow, yellow-green, or green, fleshy, oil-rich, hypanthium not persistent.

Distribution

North America, ne Mexico.

Discussion

Species 4 (3 in the flora).

Dirca mexicana G. L. Nesom & Mayfield is known from Tamaulipas, Mexico.

Selected References

Peterson, B. J., W. R. Graves, and J. Sharma. 2009. Color of pubescence on bud scales conflicts with keys for identifying species of Dirca (Thymelaeaceae). Rhodora 111: 126–130.

Schrader, J. A. and W. R. Graves. 2004. Systematics of Dirca (Thymelaeaceae) based on ITS sequences and ISSR polymorphisms. Sida 21: 511–524.

Schrader, J. A. and W. R. Graves. 2005. Seed germination of Dirca (leatherwood); pretreatments and interspecific comparisons. HortScience 40: 1838–1842.

Vogelman, H. A. 1953. Comparison of Dirca palustris and Dirca occidentalis (Thymelaeaceae). Asa Gray Bull. 2: 77–82.

Lower Taxa

Dirca decipiens, Dirca occidentalis, Dirca palustris

Key

1	Inflorescences pedunculate, flowers pedicellate; calyx unlobed or 4–5-lobed, margins shallowly crenate, erose, or undulate; bracts brown- to tan-pubescent; leaf blades usually glabrous, rarely with persistent indument.	Dirca palustris
1	Inflorescence epedunculate, flowers sessile or subsessile; calyx (3–)4-lobed, margins entire or erose; bracts white-tan tomentose; leaf blades hairy	> 2
2	Pedicels glabrous; apex of ovary and fruit glabrous; leaf margins with 6–9 cilia per mm.	Dirca occidentalis
2	Pedicels sericeous; apex of ovary and fruit with trichomes; leaf margins with 11–18 cilia per mm.	Dirca decipiens