Cryptocoryne nurii Furtado var. raubensis Ganapathy & Siow

In many cases it is a long way before a new species or variety finally becomes described. As for this var. raubensis, the first record of the "yellow nurii" is from 1985. So it took 30 year! Another clue came from Herman Bernard Ganapathy in 2002 who sent a couple of pictures of 'something new', what could be interpreted as C. nurii. Terukini 2010 also gave information and shipped live plants.
It was 2011 that Jacobsen made a trip with Ganapathy and Siow to the known localities, where they found it, partly together with C. affinis on a limestone soil.

This plant with a yellow limb of the spathe and the pallid nerves on the leaf, is found by Peter Boyce cs. in the Taman Negara F.R.(Pahang).
photo Boyce

The herbarium sheet of the "yellow nurii",
herbarium K (not really readable)

Afterwards you see the long peduncle of the spathe, not usual in C. nurii ...
photo Ganapathy
... and the spathe could be C. nurii.
photo Ganapathy
       
2011. A rather shallow stream in Pahang, Malay peninsula. Note the rapid in the centre of the picture.
photo Jacobsen

Close up of C. nurii var. raubensis.
coll. NJM11-62
photo Jacobsen

At the bank of the stream a small patch.
coll. NJM11-62
photo Jacobsen
An uprooted plant. Note the long peduncle to keep the short spathe floating on the water surface.
coll. NJM11-63
photo Jacobsen
       
The length of the peduncle is probably adapted to the water level
coll. NJM11-63
photo Jacobsen

Another uprooted raubensis with more greenish leaves.
coll. NJM11-62
photo Jacobsen

An opened syncarpium to show the seeds.
coll. NJM11-62
photo Jacobsen
There are several localities where these white veined plants grow. It looks that this character disappears in cultivation.
photo Siow
       
A typical nurii bud with forward curved limb of the spathe.
coll. AZ210-5, cult. B1356
Variation in colour of the limb...
coll. NJM11-62, cult. B1439
idem...
coll. NJM11-63G, cult. B1441
idem...
coll. NJM11-x, cult.B1512
       
Variation in color of the limb...
coll. JS, cult. B1405
idem...
coll. AZ210-5, cult, B1356
idem...
coll. AZ210-5, cult. B1356
idem.
coll. JS-NJ3429, cult. SR426
photo Reitel
       
A flowering C. nurii var. raubensis in a (normal European) hard water aquarium.
coll. NJMx, cult. NJ
photo Jacobsen
Grown emerged the peduncle stays short.
coll. NJM11-63G, cult. B1441
Male flowers and appendix on the top of the spadix.
coll. NJM11-x, cult. B1512
Distribution of C. nurii var. raubensis on peninsula Malaysia
       

As this is a limestone species, it is easy to cultivate in a hard water aquarium. But it also grows well emerged in beech tree litter.

January 2016

Literature (back to the nurii group):

Jacobsen, N., J.D. Bastmeijer, H.B. Ganapathy, K.H.N.A. Mangsor, M. Mansor, A.S. Othman, S.N.A. Rahman, R. Rusly & J. Siow. 2015. A new calcicolous variety of Cryptocoryne nurii Furtado (Araceae) from Pahang, Peninsular Malaysia. Malayan Nature Journal 2013, 65(4), 230-239. (Document service)