Cryptocoryne thwaitesii Schott

One of the most spectacular plants in the genus Cryptocoryne and a "piece de resistance" for the advanced grower.

Click on the picture to get the full image (ca 50 kB)

Habitat of Cryptocoryne thwaitesii on a shaded bank of a stream in the dry season. Note the broad ovate leaves.
coll. Waser 90-8
photo Waser
Another habitat picture. The limb of the spathe bends forward a few days after it has opened.
coll. NJ 75-14-1
photo Jacobsen
A young unfolding leaf. Note the fine undulated margin and the rough surface It feels almost like sandpaper.
coll. FW 02-2, cult .B 862
A cultivated C. thwaitesii. The leaves are almost black and reach up to 10 cm.
unknown coll., cult. Hans Ehrl
Cryptocoryne thwaitesii is quite variable in the colour of the limb of the spathe. The presence of the red dots varies from almost absent to densely covered.
coll. & cult. NJ 75-14-1
photo Jacobsen
An almost deep red limb of the spathe.
coll PB SRL01, cult. B1187
A pure white limb of the spathe. Note the brown leaves. The tube of the spathe in C. thwaitesii varies from ca. 2 - 3 cm.
coll. unknown, cult. B 1312
A broad, wide open, dense covered limb of the spathe.
coll. Tomey, cult. B 717
This wide open 'tail' is seldom seen.
coll. Waser 90-1, cult.CK
photo Kettner
Cream with dark purple red dots in the throat.
coll. Waser 02-2, cult. B 862
A yellow limb of the spathe without any purple dots.
coll. unknown, cult. M
photo Möhlmann
A quite different form of C. thwaitesii with a long and narrow tube and a whitish limb without a tail.
unknown locality, cult. B 1414
thw_x_Ehrl-B750_6071m.jpg (1992 bytes)
Variation in the colouring of the tube and the kettle.
coll. unknown, cult B 750
Densely spotted in the whole kettle.
coll. Babics SRL01, cult. B 1049
Only a few red dots in the upper part of the kettle.
coll. unknown, cult. Kaburagi
photo Kaburagi
Detail of the limb of the plant above.
unknown locality, cult. B 1414
thw-dram.jpg (6501 bytes) thwlocm.jpg (8562 bytes)
Top of the spadix with the male flowers. Note the spotted valve closing the kettle
coll. FW-SRL07-5, cult. B1183
Lower part of the spadix with the female flowers.
coll. FW-SRL07-5, cult. B1183
Drawing of C. thwaitesii in De Wit (1990)
drawing Ike Zewald
C. thwaitesii grows, like C. alba and C. bogneri in the rainforest, south west Sri Lanka

Cryptocoryne thwaitesii is best cultivated in an acid substrate. On the long term it is appropriate to cultivate it half emerged (the leaves above the water level) with the thizome and roots loosely in decomposing leaves of the beech tree. It can be grown fully emerged in pots but it is very sensitive for degrading of the soil. Cryptocoryne thwaitesii is not suitable for the hard water aquarium. Do not try this if you are not able to multiply it !
In the SW rainforest of Sri Lanka also grow, besides C. thwaitesii: C. alba, C. bogneri and C. waseri. All four are severely threatent in their habitat. That means that you should not buy it in a shop or via the internet. Find your way to specialized hobby clubs like the ECS who can multiply this beautiful plant.

Updated February 2013

Literature:

Arends, J.C., Bastmeijer, J.D. & Jacobsen, N., 1982, Chromosome numbers and taxonomy in Cryptocoryne (Araceae).II., Nord.J.Bot. 2 : 453-463.
Bastmeijer, J.D., C. Christensen & N. Jacobsen, 1984, Cryptocoryne alba und ihre Variationsbreite, Aqua-Planta 1-84 : 18-22.
Bastmeijer, J.D. & C. Kettner, 1993, Die Cryptocorynen von Yahalawatta (Sri Lanka), Aqua-Planta 1-93 : 30-31.
Graaf, A. de & Arends, J.C., 1986, The occurrence of Cryptocoryne and Lagenandra (Araceae) on Sri Lanka, Nord.J.Bot. 6 : 757-764.
Hermsen, E.P., 1977, Cryptocorynen, Het Aquarium 47(11) : 282-287.
Jacobsen, N., 1976, Notes on Cryptocoryne of Sri Lanka (Ceylon), Bot.Notiser 129 : 179-190.
Jacobsen, N., 1977, Chromosome numbers and taxonomy in Cryptocoryne (Araceae), Bot.Notiser 130 : 71-87.
Jacobsen, N., 1982, Cryptocorynen, Alfred Kernen Verlag, Stuttgart.
Jacobsen, N., 1987, Cryptocoryne, in: A Revised Handbook to the Flora of Ceylon, Vol. VI: 85-99.
Kasselmann, C., 1995, Aquarienpflanzen, Ulmer, Stuttgart.
Kawashima, J., 2001. Sri Lanka. Fish Magazine no. 422 (may 2001)(5): 27-31.
Möhlmann, F., 1987, Der Weisse Wasserkelch, Aquarien Magazin 21(11) : 436-438.
Möhlmann, F., 1993, Die Cryptocoryne-Arten Ceylons (1), Aqua-Planta 4-93 : 123-128.
Wit, H.C.D. de, 1958, A diminutive Cryptocoryne, C. thwaitesii is a little known species well worth cultivating. Fishkeeping and Waterlife, August 1958: 488-499.
Wit, H.C.D. de, 1975, Cryptocoryne alba de Wit (nov.sp.) en Cryptocoryne bogneri de Wit (nov.sp.), Het Aquarium 45(12) : 326-327.
Wit, H.C.D. de, 1990, Aquarienpflanzen, 2. Auflage, Ulmer, Stuttgart.