This species from northern Vietnam (the former Tonkin province) and southern China has been interpreted as C. crispatula var. flaccidifolia for years. It was December 2013 at the Aroid conference in Hanoi, that Jacobsen, Bogner, Ørgaard and Nguyen had the opportunity to visit the type locality where Balansa collected the type material in 1887. Only in 1941 the plant was described by Gagnepain as C. tonkinensis.

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A wide river in the Guangdong province in China. Zhou0603-1 photo Zhou	C. crispatula var. flaccidifolia is growing - nearly visible - sheltered between the boulders. coll. Zhou 0603-1 photo Zhou	More sheltered in the Guangxi province. coll. ZH2010-02 photo Zhou	Here grows it near the banks of the river.. coll. ZH2010-02 photo Zhou

The Hanoi group searching for var. tonkinensis in north Vietnam... photo Ørgaard	... quite difficult to reach the stream. photo Ørgaard	Where they found it. photo Ørgaard	An uprooted C. crispatula var. tonkinensis. photo Ørgaard

A slowly running river in S China ... coll. Zhou 0504-3 photo Zhou	... with C. crispatula var. tonkinensis... coll. Zhou 0504-3 photo Zhou	...flowering. coll. ZH2010-02 photo Zhou	Flowering abundantly! coll. ZH2012 photo Zhou

Two different colour forms growing near to each other in another river. coll. Zhou 2010-02 and -03 photo Zhou	Another dark brown coloured plant. coll. Zhou0603-1 photo Zhou	Herbarium sheet Balansa 2044 from Vietnam, type for C. crispatula var. tonkinensis	Var. tonkinensis grows easily in an aquarium. coll. ZH2010-03, cult. B1354

The rhizome tends to grow up from the soil, the plants also makes roots growing into the free water. coll. ØJV13-4, cult. B1594	The Vietnam tonkinensis grows very well in the aquarium. coll. ØJV13-4, cult. B1594	As does the Chinese C. crispatula var. tonkinensis. coll. ZH2010-03, cult. B1354	A close up of the attractive brown leaves. coll. ZH2010-03, cult. B1354

The typical Crispatula limb with a few red lines on the whitish limb. photo Zhou	The kettle from the Chinese C. crispatula var. tonkinensis. coll. Zhou 0603 photo Zhou	Globular fruits of C. crispatula var. tonkinensis coll. Zhou 0603 photo Zhou	Distribution of C. crispatula var. tonkinensis. In fact they even grow much more eastern as visible on the map.

It is not known if var. tonkinensis has a seasonal character.
For reference to the other plants and for more literature see the page on the crispatula group.

Literature:
Gagnepain, F., 1941. Aracees nouvelles Indochinoises. Not.Syst.9, 3 : 131-134. (Document service - in French)
Gagnepain, F., 1942. Cryptocoryne Fisch. Flore generale de l'Indo-Chine : 1191-1195. (Document service - in French)
Jacobsen, N., J.D.Bastmeijer, J. Bogner, V.D. Nguyen, Q.B. Hong & M. Ørgaard. 2015. The identity of Cryptocoryne crispatula var. tonkinensis (Araceae). Willdenowia 45(2) 177-182. (Document service)

Updated January 2016