Bunias

Linnaeus
Sp. Pl. 2: 669. 1753.
,
Gen. Pl. ed. 5, 300. 1754.
Common names: Hill-mustard
Etymology: Greek and Latin bunias, a kind of common mustard or turnip
Treatment appears in FNA Volume 7. Treatment on page 444. Mentioned on page 224, 227, 236, 241.

Plants not scapose; glabrous or sparsely to densely pilose (multicellular glandular tubercles or papillae present throughout, except flowers). Stems erect, often branched (many) distally. Leaves basal and cauline; petiolate, sessile, or subsessile; basal not rosulate [rosulate], petiolate, blade margins entire, pinnatifid, or lyrate; cauline sessile (subsessile distally), blade (base cuneate, attenuate), margins dentate or entire. Racemes (corymbose or paniculate), considerably elongated in fruit. Fruiting pedicels divaricate, slender. Flowers: sepals (yellowish green), oblong, (margins membranous), (glabrous, [pubescent or glandular]); petals obovate, (longer than sepals), claw distinct or absent, (apex obtuse to emarginate); stamens strongly tetradynamous; filaments (yellowish), not dilated basally [dilated]; anthers oblong [ovate], (apex obtuse); nectar glands confluent, subtending bases of stamens, median glands present. Fruits nutletlike, sessile, (readily detached from pedicel), oblong, ovoid, or subglobose, smooth, terete, 4-angled, or with 4 cristate wings, (1–4-loculed), (woody); valves (not distinct) not veined, glabrous; replum not distinct; septum subwoody or absent; ovules 2–4 per ovary; style obsolete or distinct, (slender, filiform or subconical); stigma capitate. Seeds plump [flattened], not winged, subglobose to ovoid [oblong]; seed coat (smooth), not mucilaginous when wetted; cotyledons spirolobal. x = 7.

Distribution

Introduced; Europe, Asia, n Africa.

Discussion

Species 2 (2 in the flora).

Bunias erucago and B. orientalis have the same chromosome number; the former has only about 0.8-fold of the DNA amount of B. orientalis (J. Greilhuber and R. Obermayer 1999). Although both species are widespread weeds in Europe, they have not spread much in North America.

Key

1 Fruits 4-winged, 4-loculed, (0.8-)0.9-1.3(-1.4) cm; seeds 3 or 4; petals (8-)10-13 mm; styles 3.5-5(-6) mm. Bunias erucago
1 Fruits not winged, 1- or 2-loculed, (0.5-)0.6-0.7(-0.8) cm; seeds 1 or 2; petals (4-)4.5-7(-8) mm; styles obsolete or, rarely, to 1 mm. Bunias orientalis