About Gratiola amphiantha D.Estes & R.L.Small
Gratiola amphiantha is a small aquatic plant that grows in non-Mediterranean climate vernal pools, which sometimes form in granite outcrop habitats. It is a delicate annual herb that reaches only a few centimeters in length. It has a short, threadlike stem surrounded by a rosette of tiny, lance-shaped submerged leaves. Above the submerged leaves sits a pair of slightly larger, oval-shaped floating leaves that can grow up to 8 millimeters (0.3 inches) long. Flowers grow from the leaf axils of both submerged and floating leaves. Underwater flowers are cleistogamous and never open, while open flowers that form on the water's surface have five-lobed white corollas that are a few millimeters long. This is a fast-growing species; it germinates immediately when sufficient rain is available, and matures to flower in just 17 days. Its quick life cycle is an adaptation to the very brief period that appropriate growing conditions are available in these pools. Very few other plants grow in the granite outcrop vernal pools where this species occurs, besides local endemic Isoetes species such as Isoetes piedmontana.
