Caltha

Caltha obtusa pollen polar view

Flora Antarctica Plate LXXXIV

Psychrophila leptosepala 6814

Caltha natans

Flora Antarctica part 2 plate VI

Caltha is a genus of perennial plants in the family Ranunculaceae, commonly known as marsh marigolds or kingcups. These plants are native to temperate regions of the Northern Hemisphere, including parts of Europe, Asia, and North America. Caltha species are found in wet, marshy environments such as the edges of ponds and streams, or in wet meadows. They are notable for their large, glossy green leaves and bright yellow flowers, which bloom in early spring.

Description

Caltha plants are herbaceous perennials that typically grow from rhizomes. The leaves are broad, rounded, or heart-shaped, often with a waxy or glossy appearance. The flowers of Caltha species are usually bright yellow, comprising five to nine petal-like sepals; the plants lack true petals. The flowers are solitary or borne in cymes, and they provide an important early spring nectar source for pollinators.

Species

There are several species within the genus Caltha, including:

• Caltha palustris – Commonly known as marsh marigold or kingcup, this is perhaps the most widespread and recognized species within the genus.
• Caltha leptosepala – Known as white marsh marigold or elk's-lip, found in western North America.
• Caltha natans – Floating marsh marigold, native to Siberia and parts of Asia.

Cultivation and Uses

Caltha species are popular in gardens and horticulture for their early spring flowers and their ability to thrive in wet conditions, making them suitable for water gardens, pond margins, and bog gardens. They prefer full sun to partial shade and require moist to wet soil. While most commonly found in yellow, some species and cultivars may produce white or pink flowers.

Ecology

In their natural habitat, Caltha plants play a significant role in supporting early spring pollinators by providing a source of nectar when few other flowers are in bloom. They are also used by various larvae of Lepidoptera (butterflies and moths) as food plants.

Conservation

While many species of Caltha are common and not currently at risk, their habitats, such as wetlands and marshes, are under threat from habitat destruction, pollution, and climate change. Conservation efforts are important to preserve these ecosystems and the plant and animal species that depend on them.