(Griff.) D.G. Long & A.G. Mill.
Description
Nayariophyton zizyphifolium is a little-collected shrub of the Eastern Himalayan foothills and adjacent Indo-Burmese region, known from a modest 45 georeferenced records concentrated in India (IN), Nepal (NP) and Bhutan (BT), with a peripheral occurrence in Thailand (TH). It is a plant of warm subtropical to lower temperate valleys and hill slopes, occurring in open forest, scrub and on rocky banks at low to middle elevations. The plant photographed at Karu-Chu in Bhutan at about 1800 m in May reflects this warm, sheltered river-valley habitat, well below the alpine flora and typical of the species' restricted foothill range. Under the name used here GBIF treats the record as a synonym, with Nayariophyton zizyphifolium itself standing as the currently accepted name.
It is an erect, somewhat woody shrub with stellate-pubescent young branches. The leaves are alternate, ovate to broadly elliptic with a serrate margin and a three-veined base, recalling the foliage of Ziziphus, from which the specific epithet zizyphifolium derives; they are clothed, especially beneath, with stellate hairs typical of the Malvaceae. The flowers are axillary, subtended by an epicalyx, with five sepals and five petals in the usual mallow arrangement and a column of fused stamens surrounding the style. The fruit is a schizocarpic, several-segmented mericarp characteristic of the genus, the dry segments separating at maturity.
Nayariophyton (Malvaceae) is a small, taxonomically isolated genus of the Eastern Himalaya, and the combination here reflects the revisionary work of D.G. Long and A.G. Miller for the Flora of Bhutan. Its scant collection record and narrow foothill distribution make it of biogeographic interest as an element of the Indo-Himalayan endemic flora. Given its limited known range and the conversion of low-elevation valley habitat, the species warrants attention from a conservation standpoint, though it has not been formally assessed.
Author: (Griff.) D.G. Long & A.G. Mill. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of British India, Long and Miller revision of Eastern Himalayan Malvaceae