Hornungia

Annuals [perennials]; [caudex branched]; not scapose; glabrous or puberulent, trichomes minutely branched and subsessile, mixed with simple ones. Stems erect, ascending, or decumbent [procumbent], branched or, rarely, unbranched. Leaves basal and cauline [or cauline absent]; petiolate or subsessile; basal rosulate or not, petiolate, blade margins entire, dentate, or pinnatisect; cauline petiolate or subsessile, blade margins pinnatisect, pinnatifid, dentate, or entire. Racemes (corymbose), elongated or not in fruit. Fruiting pedicels divaricate, slender. Flowers: sepals spreading or reflexed, ovate [or oblong], (glabrous or puberulent); petals white, spatulate, [obovate, oblong, or oblanceolate], (longer or shorter than sepals), claw absent, (apex obtuse or rounded); stamens (rarely 4), subtetradynamous; filaments often dilated basally; anthers ovate, (apex obtuse); nectar glands lateral, 1 on each side of lateral stamen, median glands present or absent. Fruits silicles, sessile, oblong, elliptic, obovoid [ovoid, suborbicular, lanceoloid], keeled, angustiseptate; valves each with prominent midvein, glabrous; replum rounded; septum complete; ovules [4–]10–24 per ovary; style usually obsolete (rarely to 0.5 mm); stigma capitate. Seeds biseriate or aseriate, plump, not winged, oblong; seed coat (obscurely reticulate) mucilaginous or not when wetted; cotyledons incumbent, rarely accumbent. x = 6.

Distribution

Europe, Asia, n Africa, introduced also in Mexico, South America, s Africa, Australia.

Discussion

Species 3 (1 in the flora).

R. C. Rollins (1993) recognized Hutchinsia to include the more commonly used Hymenolobus. As shown by F. K. Meyer (1982), Hutchinsia is an illegitimate name because, when described, it included the type of the earlier published Iberis Linnaeus, and he suggested that the name be replaced by Pritzelago. O. Appel and I. A. Al-Shehbaz (1998) demonstrated that the differences separating Hymenolobus and Pritzelago from Hornungia are trivial, and they adopted the latter for the combined genus. Molecular data (K. Mummenhoff et al. 2001) clearly support the placement of these taxa in one genus.

Selected References

Appel, O. and I. A. Al-Shehbaz. 1998. Generic limits and taxonomy of Hornungia, Pritzelago, and Hymenolobus (Brassicaceae). Novon 7: 338–340.

Lower Taxa

Hornungia procumbens