Lowland yellow loostrife, Mississippi loosestrife
Arizona, New Mexico and the northern Great Plains
Streambanks, marshes, wet meadows, from near sea level to 9,000 feet
Opposite, hairless, stalked; blades are elliptic to narrowly lanceolate, up to 7 inches long
July to September
Lysimachia hybrida is widespread in the eastern US, but in the West occurs mainly in central Arizona, plus a few locations in northwest New Mexico. Flowers are formed of five yellow petals, narrow at the base and irregular along the upper margin, and five pointed green sepals, a little shorter than the petals. The upper surfaces of the petals have a covering of tiny glandular hairs, densest towards the base. At the center are five short stamens, with unfused filaments. Flowers are solitary, from the upper leaf nodes.
Leaves and stems are hairless. Leaves may be whorled towards the top of the stem but are otherwise in opposite pairs, attached by stalks of up to 1.5 inches. Leaf bases may extend backwards a little, below the attachment point. Leaf margins are lined with tiny hairs.