(Wall. ex Schott) Cusimano & Hett.
Description
Sauromatum diversifolium is a tuberous aroid of the Himalaya and adjacent uplands, distributed through India, China, Nepal, Bhutan, Myanmar and Thailand, with around 146 recorded occurrences. It grows in moist temperate forest, on shaded banks, in open grassy slopes and among rocks where seasonal soil moisture is reliable, emerging with the onset of the warm season and dying back to its tuber during the dry winter. In Nepal it occupies the middle to upper montane zone, as shown by collections from Tallekh in the west at about 3000 m in June and from Samathang in the Helambu region at 2410 m in May, the latter dates coinciding with its early-season flowering.
The plant arises from a subglobose, depressed tuber and typically produces a single long-petiolate leaf whose blade is deeply pedately divided into several lanceolate to elliptic segments, the lobes acuminate and the petiole often mottled. The inflorescence is a typical aroid spadix subtended by a spathe, the spathe tube convolute and the limb expanded, lanceolate and often dull purple or marked within. The spadix bears a sterile terminal appendix above separated zones of female and male flowers, and emits a faint odour at anthesis to attract small dipteran and beetle pollinators. The fruiting head is a cluster of small berries.
The species was transferred to Sauromatum by Cusimano and Hettich on molecular and morphological evidence that united the former Typhonium diversifolium with the saururoid lineage. The genus is protogynous and largely sapromyophilous, with thermogenic spadices that volatilise scent to lure pollinators into the floral chamber. Widespread and locally frequent in suitable montane habitat, S. diversifolium is not regarded as threatened, though like many tuberous aroids it is sensitive to grazing pressure and the loss of forest-edge microhabitats.
Author: (Wall. ex Schott) Cusimano & Hett. · Sources: POWO (Kew), GBIF, Flora of China Vol. 23, Flora of Bhutan Vol. 3, Flora of Nepal, Cusimano et al. molecular phylogeny of Areae (Araceae)