Flora of Bhutan gives the following keys:
1. Leaves coarsely crenate; calyx with a few hairs extenally; disc lobes triangular; capsules with glabrous remains of calyx …. 1. G. leptostachya
+ Leaves finely serrate or crenate-serrate; calyx densely appressed pubescent extenally; disc lobes linear; capsules with pubescent remains of calyx … 2. G. napalensis
Gouania leptostachya DC. (China (Guangxi, Yunnan), Vietnam, Laos, Myanmar [Burma] (Taninthayi, Yangon), Bhutan, Nepal, peninsular Malaysia, Philippines (Luzon to Mindanao), India (Assam, Darjeeling, Uttar Pradesh, West Bengal, Orissa, Maharashtra), Andamans (North Andamans, Middle Andamans, South Andamans, Little Andaman Isl.), Nicobars (Car Nicobar Isl., North Nicobars, Central Nicobars, Great Nicobar Isl., Little Nicobar Isl.), Bangladesh as per Catalogue of Life)
Gouania microcarpa DC. (India (Punjab), Jammu & Kashmir, Malaysia, Myanmar [Burma] (Bago, Mon, Taninthayi), Sri Lanka, Indonesia as per Catalogue of life & Maharastra, Karnataka & Kerala as per ENVIS – FRLHT)
Gouania napalensis Wall. (Nepal, Sikkim, Bhutan, India (Punjab, Uttar Pradesh, Darjeeling, Bihar, West Bengal, Meghalaya, Assam) as per Catalogue of Life)
Gouania leptostachya DC. (Himalaya (Kumaun to Assam), Burma, Indo-China, Malaysia)
Gouania napalensis Wall. (Himalaya (Nepal, Sikkim))
Some species found in India with description from Flora of China
other than China]:
Gouania leptostachya Candolle [Bhutan, India, Laos, Malaysia, Myanmar, Nepal, Philippines, Singapore, Thailand, Vietnam].
Flora of Eastern Ghats : hill range of South East India By T. Pullaiah, D. Muralidhara Rao (2002):
Gouania (Rhamnaceae) page with images of species in efloraofindia : 5 posts by 2 authors.
I request you to pl. go through & point out mistakes, if any. I hope this will aid in identifications in future. If anybody can send images of other species of this genera (for incorporation in the website), if any, or can identify unidentified images, it will be really nice.