Branched broomrape (Orobanche ramosa)
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Branched broomrape is an annual and sometimes perennial parasitic plant that has no chlorophyll and lacks conspicuous leaves. It attaches to plant roots and is visible above ground only when flowering and inhabits ornamental and vegetable crop fields and margins, especially tomato fields. Branched broomrape is found in the San Francisco Bay region, northern San Joaquin Valley, eastern South Coast Ranges, and Southwestern regions up to an elevation of about 160 feet (50 m). It is an A-rated (“A”–Eradication, containment, rejection, or other holding action at the state-county level. Quarantine interceptions to be rejected or treated at any point in the state) noxious weed in California. If you find it, contact your agricultural commissioner.
Seedlings grow below ground.
The young plant looks like a yellowish spear or spike.
The mature plant is 4 to 12 inches (10–30 cm) tall. The aboveground parts are pale to bright yellow. Stems are slender, covered with very short glandular hairs, and have many branches arising from the base. Leaves are reduced to scales that alternate along the stem.
Branched broomrape blooms from late June through September in crop fields with irrigation and suitable host plants. In natural areas, the flowers may appear later, coinciding with rain in October and November. Flowers resemble small snapdragons, ranging in color from white to blue or violet. Twenty or more flowers cluster to form a spike-shaped flower head. Upper flowers are stalkless and lower flowers are short stalked. Stems and flower heads are covered with very short glandular hairs.
The fruit is a one-chambered capsule that opens by two valves at the tip.
Seeds are angular to egg shaped and yellowish brown, with a dull and netlike surface.
Branched broomrape reproduces by seed, which spread in water and in contaminated soil.