09-21-2015, 10:18 AM
Join Date: Mar 2006
Location: Brunswick, Germany
iTrader Positive Rating: 100%
| | Re: Cryptocoryne crispatula var. tonkinensis
I don't know if the very narrow-leaved plant in the UKAPS link is cultivated in the U.S., it's at least available as potted and in-vitro plant with the label C. tonkinensis in Europe.
But by this way I want to call attention to the Jacobsen & al. paper in your second link:
1) It has turned out that the very narrow-leaved plant (also shown in the UKAPS forum) that's currently called C. tonkinensis or C. crispatula var. tonkinensis, is NOT tonkinensis in the original sense. It comes from eastern Thailand, Khao Yai and Ubon Ratchathani. It is a taxon of its own, not yet formally named.
2) The type specimen of tonkinensis was found in North Vietnam (Tonkin), and corresponding plants occur also in southeastern China. The leaves of this true tonkinensis are much more similar to C. crispatula var. flaccidifolia (originally from southern Thailand), broader than those of the very narrow-leaved eastern Thailand plant. This requires re-definition of var. flaccidifolia.
I don't know to what extent the true (broader-leaved) C. crispatula var. tonkinensis is cultivated as aquarium plant. The name C. tonkinensis is long known in the hobby, and old pictures show a var. flaccidifolia-like plant - maybe true tonkinensis. Flaccidifolia-like plants are often still labeled "C. retrospiralis" (erroneous, true retrospiralis comes from India), and maybe also original tonkinensis is among them.
The name changes will surely cause a lot of confusion in the hobby...