Prostrate vervain (Verbena bracteata) flowers and fruits. Bottom right: the tip of an inflorescence of prostrate vervain. Note the five lobes (“petals”) at the apex of the tubular corolla and the narrow, hairy bracts beneath each flower. Top right: the tips of two prostrate vervain flowers with several flower buds immediately above them. Note that two of the “petals” are markedly larger than the other three and that the throat of the corolla is largely occluded by in-pointing hairs; the stamens and style are not visible externally. Left: an inflorescence of prostrate vervain. A few flowers are visible at the tip as patches of color. The remainder of the inflorescence consists of the hairy bracts that sat beneath the (now fertilized) flowers, remnants of the flower calyxes, and the capsule containing four nutlets that developed from the ovary of the flower. White arrows point to a few of the capsules.
Prostrate vervain stems produce dense spikes of flowers at their tips. Beneath each flower is a 3/4″ long, narrow bract with long, whitish hairs; the bracts make up the erect or sprawling flower spike (6″ long, 3/4″ across), with blooming flowers at the tip and fruits maturing below. Individual flowers are about 1/8″ across, with a narrow, very hairy, basal calyx extending into five sharply pointed lobes, and a narrow, tubular corolla that abruptly flares into five rounded lobes (“petals”) surrounding a white or greenish-white throat; the upper two lobes are slightly smaller than the lower three. Both the calyx and corolla are the same color whether light blue, purple, or pink. Hidden in the throat of the corolla are four stamens with yellow anthers and a short style. The fruit consists of a capsule containing four nutlets that is nestled in the remains of the calyx. This plant is a pioneer in highly degraded habitats that is especially fond of cracks and crevices — despite its weedy appearance, prostrate vervain is a native species. In spite of the tiny size of its anatomical characters, this is a relatively straightforward plant to confidently identify from the hairy stems, leaves, and flower spikes and the tiny, lavender apical flowers.
Prostrate vervain (Verbena bracteata) stems and leaves. Top: the very hairy stem and several leaves of prostrate vervain; some of the leaves have been truncated by a lawn mower. Bottom right: two intact and well-displayed leaves of prostrate vervain. Bottom left: a hairy stem of prostrate vervain with several branches. Note the leaves on the left of the image and a new inflorescence beginning to develop on the right.
Prostrate vervain (aka, big-bract vervain, creeping vervain) is a native annual (or sometimes perennial), an inconspicuous, low, sprawling, plant, 6-8″ high. In open areas prostrate vervain can form a circular mat of stems and leaves. The stems are 6-18″ long, moderately square in cross section (four-angled), profusely covered with long, white, spreading hairs. The leaves are up to 3″ long and 1″ wide but usually much smaller, opposite, and have abundant white hairs, especially on the underside and margins. Lower stem leaves have two relatively small basal lobes (missing in the upper stem leaves) and a terminal lobe, some with additional small lobes along the margins (approaching pinnatifid).
A dense patch of prostrate vervain (Verbena bracteata) growing on the lawn south of the Griffin Museum of Science and Industry.
Prostrate vervain (aka, big-bract vervain, creeping vervain) is a native annual (or sometimes perennial), an inconspicuous, low, sprawling, plant, 6-8″ high. In open areas prostrate vervain can form a circular mat of stems and leaves. The stems are 6-18″ long, moderately square in cross section (four-angled), profusely covered with long, white, spreading hairs. The leaves are up to 3″ long and 1″ wide but usually much smaller, opposite, and have abundant white hairs, especially on the underside and margins. Lower stem leaves have two relatively small basal lobes (missing in the upper stem leaves) and a terminal lobe, some with additional small lobes along the margins (approaching pinnatifid). The stems produce dense spikes of flowers at their tips. Beneath each flower is a 3/4″ long, narrow bract with long, whitish hairs; the bracts make up the erect or sprawling flower spike (6″ long, 3/4″ across), with blooming flowers at the tip and fruits maturing below. Individual flowers are about 1/8″ across, with a narrow, very hairy, basal calyx extending into five sharply pointed lobes, and a narrow, tubular corolla that abruptly flares into five rounded lobes (“petals”) surrounding a white or greenish-white throat; the upper two lobes are slightly smaller than the lower three. Both the calyx and corolla are the same color whether light blue, purple, or pink. Hidden in the throat of the corolla are four stamens with yellow anthers and a short style. The fruit consists of a capsule containing four nutlets that is nestled in the remains of the calyx. This plant is a pioneer in highly degraded habitats that is especially fond of cracks and crevices. Despite its weedy appearance, prostrate vervain is a native species. In spite of the tiny size of its anatomical characters, this is a relatively straightforward plant to confidently identify from the hairy stems, leaves, and flower spikes and the tiny, lavender apical flowers.


