Cryptocoryne cordata Griffith var. siamensis (Gagnepain) N. Jacobsen & D. Sookchaloem

Cryptocoryne cordata var. siamensis originates from the limestone in peninsula Thailand, what means that the water is not as acid as for the other members of the cordata-group. It became from the 60s a very popular aquarium plant under the name "Cryptocoryne blassii" because of its broad, brown leaves with a wine red lower side. From the 80s, Jacobsen made many trips in that area and found a lot of variation in leaf form and colour, as for the limb of the spathe. See the Synonyms page for changes in the names.

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A small stream on peninsular Thailand with on the sheltered side stands of C. cordata var. siamensis.
coll. NJT 03-01
photo Jacobsen
A close up of this patch. The leaves are coffee brown on the upper side.
coll. NJT 03-01
photo Jacobsen
The same stream with plants which are more greenish.
coll. NJT 03-01
photo Jacobsen
Again the same stream. The limb of the spathe varies from bright yellow to brownish.
coll. NJT 03-01
photo Jacobsen
       
Another part of the stream in peninsular Thailand. You see the wine red lower sides of the leaves.
coll. CC 204-1
photo Christensen
There are very many streams in peninsular Thailand with C. cordata var. siamensis. All slight different.
coll. NJT 04-31
photo Jacobsen
C. cordata var. siamensis also grows in this very deep spring.
coll. NJT 02-15
photo Jacobsen
Fresh collected plants.
coll. NJT 02-15
photo Jacobsen
       
An aquarium picture of C. cordata var. cordata. The plants tolerate high Ca levels.
coll. unknown
photo Möhlmann
In shallow water, the leaves reaches the surface. The spathe grows out of the water, making pollinating possible by small flies, which might be attracted by the odour of the inflorescence. Note the slight bullate leaves.
coll. unknown, cult. Bot. G. Copenhagen
photo Jacobsen
The 'classical' C. cordata var. siamensis ("blassii") has a more or less developed brown tinge over the limb, most prominent on the edges. The (bullated) leaves are broad cordate to ovate and can be quite brown and have a deep purple red lower side.
coll. unknown, cult. B 17
The leaves of this plant are very dark with fine purple dots on it. The lower side deep purple. The limb is brownish at the edges. Note the somewhat swollen throat, called a collar zone.
coll. unknown, cult. B 290
       
The limb is quite glossy. The leaves are ovate and have a brownish upper side and a deep purple lower side of the leaves.
coll. unknown, cult. B 16
A more reddish limb of the spathe Note also the much more swollen collar zone.
coll. NJT03-1B
photo Jacobsen
Tomey collected this plant in the north of W. Malaysia. It is not certain if we must attribute it to C. cordata var. siamensis.
coll. Tomey s.n., cult B 295
This plant has big cordate leaves without any purple, the upper side dark green, the lower side is pale green. The chromosome number is however 2n = 85.
coll. unknown, cult. B 18
       
Opened kettle showing the spadix with the female flowers (bottom) and the male flowers (above). Note the purplish appendix on top ands the white kettle wall inside.
coll. NJT02-5A, cult. B 868
Compared to the picture left, note the dark styles of the female flowers and the red colour of the lower part of the kettle.
coll. NJT02-14, cult B 881
In the 70s Mr. Schneider from Zugzen (CH) discovered a deviant specimen in an import shipment. This plant is described as Cryptocoryne cordata 'Rosanervig'. Unfortunately, the (mostly) rose veins may be less pronounced under some conditions.
coll. unknown, cult B 619
Opened kettle of .Cryptocoryne cordata 'Rosanervig'. Nicely intermediate in characteristics.
coll. unknown, cult B 619
       
Isotype of C. cordata var. siamensis collected in peninsular Thailand.
coll. Kerr 17094
Nationaal Herbarium Leiden
Drawing of the holotype (Kew herbarium) in de Wit 1990.
coll. Kerr 17094
drawing Ike Zewald
Drawing of the type specimen of "C. blassii"   also in de Wit 1990. The short naked axis between the male and the female flowers is not typical.
coll. unknown, cult. Blass
drawing Ike Zewald
Distribution of C. cordata var. siamensis on the peninsular Thailand and - probably - the very north of West Malaysia.
       

Cultivation is quite easy in water with hardness up to 25 DH. The plants easily reach up to 20 - 30 cm, making them much wanted by aquarists.

Brian Seccombe (AUS) made a time lapse photo series of the opening of the limb, see his movie.

See also the other Cryptocoryne of the cordata-group

Updated July 2012

Literature: see the cordata-group.