Verbena L.

Flora Zambesiaca. Vol 8, Pt 7. Avicenniaceae, R. Fernandes. Nesogenaceae, M.A. Diniz. Verbenaceae, R. Fernandes. Lamiaceae, R. Fernandes. 2005.

Morphology General Habit

Annual or perennial herbs, small shrubs, woody climbers or trees Annual or perennial herbs, small shrubs, woody climbers or trees.

Morphology Stem

Stems 4-angled, erect ascending or procumbent, glabrous or hairy Stems 4-angled, erect ascending or procumbent, glabrous or hairy.

Morphology Leaves

Leaves opposite and usually decussate, rarely 3-whorled or alternate, dentate, or often incised or variously lobed or partite, rarely entire Leaves opposite and usually decussate, rarely 3-whorled or alternate, dentate, or often incised or variously lobed or partite, rarely entire.

Morphology Reproductive morphology Inflorescences

Inflorescences spicate with the spikes terminal, sometimes axillary, simple or corymbosely or paniculately arranged; spikes densely crowded, or elongate with distant flowers Inflorescences spicate with the spikes terminal, sometimes axillary, simple or corymbosely or paniculately arranged; spikes densely crowded, or elongate with distant flowers.

Morphology Reproductive morphology Flowers

Flowers small or medium-sized, sessile, each solitary in the axil of a narrow bract Flowers small or medium-sized, sessile, each solitary in the axil of a narrow bract.

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary 2-carpellate, entire or slightly lobed at the apex, 4-locular at anthesis, each locule l-ovulate; ovules anatropous, erect, attached laterally at or near the base; style usually equalling the stamens, divided at the apex into a short, stigmatic anterior lobe and an acute horny sterile posterior tooth

Note

The species found the Flora Zambesiaca area, with the exception of Verbena officinalis subsp. africana , are all introduced and most have become naturalized.  Taxa which occur the Flora Zambesiaca area only as cultivated garden ornamentals include: Verbena wrightii A. Gray, Verbena × hybrida Groenl. & Rümpler and Verbena × teasii Moldenke. The concept of Verbena employed here includes Glandularia J.F. Gmel. which has often been recognized as a separate genus, e.g. by Sanders, R.W., Harvard Papers Botany 5 , 2: 303–358 (2001).   The treatment of V. bonariensis L., V. brasiliensis Vell. and V. litoralis Kunth by  Dr. P. Yeo,  Kew Bull. 45 : 101–120 (1990), is followed here.

Distribution

A genus of c. 350 taxa (including species and infraspecific taxa), mostly native to temperate and tropical America, with 2 species Europe, Asia and N Africa.  Several species, and their hybrids, are introduced in the Old World as garden ornamentals.

Morphology Reproductive morphology Flowers Calyx

Calyx tubular, 5-angled and ribbed on the angles, unequally 5-toothed, ± dilated at the base in the fruiting stage and then ventricose, eventually splitting. Calyx tubular, 5-angled and ribbed on the angles, unequally 5-toothed, ± dilated at the base the fruiting stage and then ventricose, eventually splitting

Morphology Reproductive morphology Flowers Corolla

Corolla funnel-shaped or hypocrateriform; tube straight or curved, cylindric or widening slightly towards the apex, usually villous within particularly at the mouth and about the insertion of the filaments; limb spreading, oblique, weakly 2-lipped, with unequal obtuse lobes, rounded or emarginate at the apex. Corolla funnel-shaped or hypocrateriform; tube straight or curved, cylindric or widening slightly towards the apex, usually villous within particularly at the mouth and about the insertion of the filaments; limb spreading, oblique, weakly 2-lipped, with unequal obtuse lobes, rounded or emarginate at the apex

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, included, didynamous; filaments inserted about or above the middle of the corolla tube; anthers ovate, with parallel or diverging thecae without appendages, or the connectives of upper 2 stamens each provided with a clavate or glanduliform appendage. Stamens 4, included, didynamous; filaments inserted about or above the middle of the corolla tube; anthers ovate, with parallel or diverging thecae without appendages, or the connectives of upper 2 stamens each provided with a clavate or glanduliform appendage

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 2-carpellate, entire or slightly lobed at the apex, 4-locular at anthesis, each locule l-ovulate; ovules anatropous, erect, attached laterally at or near the base; style usually equalling the stamens, divided at the apex into a short, stigmatic anterior lobe and an acute horny sterile posterior tooth.

Morphology Reproductive morphology Fruits

Fruit a schizocarp, enclosed within the persistent calyx, separating when ripe into four 1-seeded mericarps; mericarps linear or oblong, with dry pericarp, longitudinally ribbed with a raised reticulation toward the apex. Fruit a schizocarp, enclosed within the persistent calyx, separating when ripe into four 1-seeded mericarps; mericarps linear or oblong, with dry pericarp, longitudinally ribbed with a raised reticulation toward the apex

Morphology Reproductive morphology Seeds

Seeds oblong; endosperm lacking or scanty. Seeds oblong; endosperm lacking or scanty.