Platostoma is a genus of flowering plants in the mint family, Lamiaceae, first described as a genus in 1818. It is native to tropical parts of Africa, southern Asia, Papuasia, and Australia. Mesona and Acrocephalus has been known as its synonyms.
A widely consumed species in this genus is Platostoma palustre (synonyms Mesona chinensis, M. elegans, and M. procumbens), or xiancao (仙草) in Mandarin, sian-chháu (仙草) in Taiwanese, leung fun cho (涼粉草) in Cantonese, sương sáo in Vietnamese, and cincau in Indonesian and Malay. It is eaten as a snack in drinks, or set as a gel and served as a grass jelly.
In Indonesia the Platostoma palustre leaf is used to make a black jelly; there is also an instant powder variety available.
Species
There are about 44-46 accepted species as below: Platostoma africanum P.Beauv — tropical Africa, southern India, Lesser Sunda Islands in Indonesia Platostoma annamense (G.Taylor) A.J.Paton — Vietnam, Thailand, Cambodia Platostoma axillaris (Benth.) A.J.Paton — Assam Platostoma becquerelii Suddee & A.J.Paton — Cambodia Platostoma borzianum (Chiov.) ined.. — Ethiopia Platostoma calcaratum (Hemsl.) A.J.Paton — southern China, northern Indochina Platostoma cambodgense Suddee & A.J.Paton — Vietnam, Thailand, Cambodia, Laos Platostoma clausum (Merr.) A.J.Paton — Culion Island in Philippines Platostoma cochinchinense (Lour.) A.J.Paton — southern China, Indochina, Java, Sumatra Platostoma coeruleum (R.E.Fr.) A.J.Paton — Angola, Zambia Platostoma coloratum (D.Don) A.J.Paton — Yunnan, eastern Himalayas, northern Indochina Platostoma denticulatum Robyns — central Africa from Cameroon east to Tanzania and south to Angola Platostoma dilungense (Lisowski & Mielcarek) A.J.Paton — Zaïre, Tanzania, Zambia, Malawi Platostoma elongatum (Benth.) A.J.Paton — Sri Lanka, southern India Platostoma fastigiatum A.J.Paton & Hedge — Madagascar Platostoma fimbriatum A.J.Paton — Thailand Platostoma gabonense A.J.Paton — Cameroon, Gabon, Tanzania Platostoma glomerulatum A.J.Paton & Hedge — Madagascar Platostoma grandiflorum Suddee & A.J.Paton — eastern Indochina Platostoma helenae (Buscal. & Muschl.) ined.. — Mozambique Platostoma hildebrandtii (Vatke) A.J.Paton & Hedge — Kenya, Tanzania Platostoma hispidum (L.) A.J.Paton — Southeast Asia, southern China, Assam, New Guinea Platostoma intermedium A.J.Paton — Thailand Platostoma kerrii Suddee & A.J.Paton — Thailand, Cambodia Platostoma lanceolatum (Chermsir. ex Murata) A.J.Paton — Thailand Platostoma laxiflorum A.J.Paton & Hedge — Madagascar Platostoma leptochilon Robyns — Zaïre Platostoma longicorne (F.Muell.) A.J.Paton — Queensland, New Guinea Platostoma madagascariense (Benth.) A.J.Paton & Hedge — Madagascar Platostoma mekongense Suddee — Thailand Platostoma menthoides (L.) A.J.Paton — Sri Lanka, southern India Platostoma montanum (Robyns) A.J.Paton — Zaïre, Tanzania, Rwanda, Burundi Platostoma ocimoides (G.Taylor) A.J.Paton — Thailand, Cambodia Platostoma palniense (Mukerjee) A.J.Paton — southern India Platostoma palustre (Blume) A.J.Paton — Southeast Asia, southern China, Assam, Bangladesh, New Guinea Platostoma rotundifolium (Briq.) A.J.Paton — tropical and southern Africa Platostoma rubrum Suddee & A.J.Paton — Thailand, Laos Platostoma siamense (Murata) A.J.Paton — Thailand Platostoma stoloniferum (G.Taylor) A.J.Paton — Thailand, Laos Platostoma strictum (Hiern) A.J.Paton — Zaïre, Angola, Zambia, Malawi Platostoma taylorii Suddee & A.J.Paton — Thailand, Cambodia Platostoma tectum A.J.Paton — Thailand, Cambodia, Laos Platostoma tenellum (Benth.) A.J.Paton & Hedge — Madagascar Platostoma thymifolium (Benth.) A.J.Paton & Hedge — Madagascar Platostoma tridechii Suddee — Thailand Platostoma verbenifolium (Watt ex Mukerjee) A.J.Paton — Assam, Bangladesh, Arunachal Pradesh, Myanmar