About Plantago arenaria Waldst. & Kit.
Plantago arenaria Waldst. & Kit. (also referred to as Plantago indica) is an annual herb with a taproot and an erect, hairy stem. Its leaves are arranged oppositely or in whorls of three to five, with elongated internodes between leaf clusters. Glandular hairs (glandular pubescence) cover the stems, leaves, sepals, and inflorescences. The leaves are simple, linear or lanceolate in shape, with a base that runs down along the petiole. Leaf margins are entire or slightly toothed; mature leaves measure 2.5–5 cm (1.0–2.0 in) long and 1–3 mm wide. Some leaves are modified into bracts 0.5 to 2 cm (0.2 to 0.8 in) long, with a pointed cuspidate apex and a round-ovate base. This plant produces a densely flowered inflorescence. Individual flowers have a hairless, brownish corolla, and a calyx made of elliptic to obovate sepals with prominent broad veins. Stamens extend outward beyond the corolla; their anthers are yellow, ellipsoid, and 1.8–2.2 mm long. The stigma's style also extends well beyond the corolla. All floral parts are hypogynous, positioned above the ovary. Fruits are capsules that each contain 2 seeds. The seeds measure 2.5–2.8 mm, are black or blackish-brown, shiny, ellipsoid, and have a clear central groove on their inner face. This species is native to North Africa, most of Europe excluding the far north, and southwest Asia ranging from Jordan to Turkey and Iran, as well as western and central Russia, Kazakhstan, Kyrgyzstan, and Tajikistan. It has become widely naturalized in parts of Australia, China, India, Japan, Pakistan, and North America, and occurs more locally in South America. It grows most commonly in sandy habitats such as arid deserts and sandy beaches, and can also be found on roadsides and alongside railroad tracks. Its seeds, sold under the common names French psyllium or black psyllium, are cultivated for medicinal use alongside other psyllium species such as P. ovata. Mucilage extracted from the seed coat is used as a laxative for constipation, and to treat irritable bowel syndrome (IBS) and diarrhea. Seed mucilage has also been reported to lower the risk of coronary heart disease.
