''Caltha dioneaefolia'' is a dwarf

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

herb, of the Buttercup Family (Ranunculaceae) with apparently seated pale yellow flowers with about seven stamens and two to three free carpels and leaves that are reminiscent of those of the Venus flytrap, but very small and with leaflike appendages on the leaf. It occurs in the southern Andes of Chile and Argentina, including on Tierra del Fuego and Hermite Island.

Description

''Caltha dioneaefolia'' often grows in dense clusters over considerable areas, with thick rhizomes. The stems may be four to ten cm long and are densely branched. Its shiny, thick and fleshy leaves consist of a broad and long leafstalk, about half as wide and up to three times as long as the blade. The blade itself consists of two parts which are approximately identical in shape, but not in size. The larger, lower part is folded over its mid vein, about cm long, ovate or almost circular, split into left and right lobes, and concave. The smaller, upper or inner part, which is often referred to as appendages, also consists of two ovate lobes of about 3 mm long. All four lobes have an entire margin which carries teeth-like hairs that are bent slightly inwards for the large lobes and outward for the small appendages. Each pair so resembles a trapleaf of the carnivorous

Venus flytrap The Venus flytrap (''Dionaea muscipula'') is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. It catches its prey—chiefly insects and arachnids—with a trapping ...

''Dionaea muscipula''. The leaf surface however harbors neither glands, nor trigger hairs, and hence ''C. dioneaefolia'' is not a carnivorous plant. The appendages are homologous with the ears at the base of the leafblade of Northern Hemisphere ''Caltha'' species. The purpose of the leaves' unusual structure is not presently known. The

actinomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

solitary flowers of about 1 cm across have five spreading, egg-shaped, yellow

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s, with about nine parallel veins on a short peduncle of about –1 cm, making it appear seated in the hart of the rosette of leaves. There are usually seven stamens. The two or three ovaries each contain two to five

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the '' integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the ...

s. There are forty eight chromosomes (2n=48).

Distribution and ecology

The species occurs in the Southern Andes. Bogs near the Strait of Magellan are densely coated by patches of ''C. dioneaefolia'', '' Gaimardia'' and ''

Astelia ''Astelia'' is a genus of flowering plants in the recently named family Asteliaceae. They are rhizomatous tufted perennials native to various islands in the Pacific, Indian, and South Atlantic Oceans, as well as to Australia and to the southern ...

'', that grow in between ''

Sphagnum ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, peat moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store wa ...

'' and other mosses.

References

{{Taxonbar, from=Q22286978 dioneaefolia Plants described in 1843 Flora of Chile Flora of Argentina Taxa named by Joseph Dalton Hooker