Balsaminaceae

Balsaminaceae

Impatiens tripetala

Balsaminaceae

Impatiens florigera

Balsaminaceae

Impatiens puberula

Balsaminaceae

Impatiens scitula

Balsaminaceae

Balsaminaceae

Impatiens sulcata

by GP Jürgens

Wall.

Bh09 387 P613
Bhutan Mo-Chu, 1500m June

Description

Impatiens sulcata is a tall, robust annual balsam of the Himalaya, recorded by GBIF (361 occurrences) from India, Nepal, Bhutan, Pakistan and adjacent China and Myanmar. It favours damp, nutrient-rich ground along streams, ditches, forest margins, roadside seepages and disturbed moist sites, principally from around 1500 to 3000 m in the warm-temperate and subtropical belts. The cited gathering from the Mo-Chu in Bhutan at 1500 m in June reflects its riparian preference, the plant typically forming dense, gregarious stands in the early monsoon along watercourses where the soil remains saturated.

The species is a succulent herb often exceeding a metre in height, with stout, conspicuously grooved (sulcate), reddish, hollow stems that root at the lower nodes. The leaves are large, ovate to ovate-lanceolate, serrate with crenate-glandular teeth, and arranged oppositely or in whorls toward the apex. Flowers are large and showy, pink to purplish, borne in axillary racemose clusters; the lower sepal forms a saccate spur, the standard is dorsally carinate, and the lateral united petals carry broad auricles. The fruit is a fleshy, club-shaped capsule that dehisces explosively, scattering the seeds by elastic recoil of the valves.

Belonging to the speciose, taxonomically complex genus Impatiens, the species sits among the tall Himalayan annual balsams and is allied to such forms as I. glandulifera, with which it shares vigorous growth and explosive seed dispersal. Its annual, fast-growing, ruderal habit makes it an effective colonist of disturbed riparian ground, while its open flowers are pollinated by bees and butterflies. It is widespread and not threatened.

Author: Wall. · Sources: POWO (Kew), GBIF, Flora of China Vol. 12, Flora of Bhutan Vol. 1, Flora of Nepal, Grey-Wilson Impatiens of Africa and the Himalaya

Balsaminaceae

Impatiens uncipetala

by G & P Jürgens

C.B.Clarke ex Hook.f.

Bhutan2015 91
Bhutan Galephug 1200m, October

Description

Impatiens uncipetala is a Himalayan balsam recorded from India, Nepal, China and Bhutan, with 43 georeferenced occurrences across the central and eastern Himalaya. As with most Impatiens it is a moisture-demanding herb of shaded, humid habitats, growing along stream banks, on dripping rock faces, in ditches and on the floor of moist subtropical to lower temperate forest. The plant photographed at Galephug in Bhutan at 1200 m in October reflects its low-elevation, post-monsoon flowering, when the soft, succulent annuals reach maturity and bloom freely in the warm, wet foothill forests.

The plant is a tender annual herb with translucent, watery, brittle stems that are often swollen at the nodes and root readily where they touch the ground. The leaves are simple, alternate or sometimes subopposite, ovate to lanceolate, with toothed margins. The zygomorphic flowers hang on slender pedicels and display the characteristic balsam architecture: three sepals, the lowermost enlarged into a saccate nectar spur, and five petals in which the two lateral pairs are fused into wing-like structures. The epithet uncipetala refers to a hooked petal appendage. The fruit is a fleshy, five-valved capsule that splits and coils explosively, ejecting the seeds.

Impatiens is one of the largest angiosperm genera, with a major centre of diversity in the Sino-Himalayan and Indo-Burmese region where narrowly endemic species abound. Its explosive capsules and reliance on humid microhabitats foster localised, often patchy distributions. The moderate occurrence count for I. uncipetala suggests a regional but uncommon species best conserved through maintenance of intact moist forest.

Author: C.B.Clarke ex Hook.f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Impatiens of the Himalaya and China monographic studies (Balsaminaceae), Flowers of the Himalaya (Polunin & Stainton)

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