About Paraquilegia microphylla (Royle) J.Drumm. & Hutch.
Paraquilegia microphylla (Royle) J.Drumm. & Hutch. is a species of perennial herb in the genus Paraquilegia, family Ranunculaceae. This species shows high morphological variability, especially in leaf traits and flower color. It is overall similar to Paraquilegia anemonoides and Paraquilegia caespitosa, but can be distinguished by its generally smaller, glabrous biternate leaves. Its biternate leaves grow on petioles 2.5 to 11 cm (0.98 to 4.3 in) long. As a cushion plant, mature individuals can reach or occasionally exceed 40 cm (16 in) in total width. Over multiple growing seasons, the densely packed stems become covered by the remains of old petioles. Stem arrangement is one of the variable traits of the species: some plants are tightly tufted with short, densely packed stems, while others, even within the same population, have thinner, more loosely arranged stems.
Flowering occurs from May to August. Flowering stems grow 30 mm (1.2 in) to 150 mm (5.9 in) tall, and open flowers are 2.8 cm (1.1 in) to 5 cm (2.0 in) in diameter. All species in the genus Paraquilegia have five sepals and five shorter yellow petals. For P. microphylla, sepals are usually purple to purplish red, with rare white individuals. Flower color varies across the species' range: western Himalayan populations have small white flowers, while eastern Himalayan populations produce larger lilac flowers. Fruiting takes place in August and September. The fruits of P. microphylla are occasionally partially developed before sepals are shed, but this happens less often than in P. caespitosa.
Seeds of P. microphylla are smooth, hairless, brown, narrowly ovoid, and narrowly winged, measuring 1.3 mm (0.051 in) to 1.8 mm (0.071 in) long. Seeds typically require at least two years to germinate. American botanist and gardener Robert Nold described the resulting seedlings as "incredibly small and look[ing] exactly like columbines dancing on the head of a pin".
Paraquilegia microphylla is native to an extensive range covering Siberian Russia, Central Asia, the Himalayas, and eastwards to Japan. It grows throughout most of the Himalayas, only absent from the westernmost parts of the range. In China, it occurs in mountainous western regions, including Tibet (Xizang), Sichuan, and Xinjiang. The Flora of China also records its presence in Kazakhstan, Nepal, northern Pakistan, Sikkim (Bhutan), and Tajikistan.
This species favors alpine and subarctic climates. It grows mainly on cliffs and in rock fissures at altitudes from 2,700 m (8,900 ft) to 4,300 m (14,100 ft), and rarely grows on sloping rocky meadows. It prefers limestone soil.
Members of the genus Paraquilegia are cultivated by rock gardeners, and Nold noted that the genus is generally considered to only be grown successfully by "the most experienced growers". P. microphylla is the most common Paraquilegia species in cultivation, though it remains relatively rare. When exhibited, it is often misidentified as P. anemonoides. During the 20th century, multiple seed-collecting expeditions to western China and the Himalayas brought seeds of this species back to the United Kingdom and the United States.
