Cryptocoryne jacobsenii de Wit

A 'difficult' species in the sense that we don't know its distribution and that different forms are interpreted to belong to this species. More research is necessary to clear up these problems. As far as I know, there are no plants of either forms in cultivation.

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Cryptocoryne jacobsenii was shipped to Europe in the 70's. The origin was said to be the Malay peninsula / Sumatra. This is a picture of the TYPE specimen.
unknown locality, cult. NJ 2864
photo Jacobsen
The leafs of C. jacobsenii are rather small with some transverse markings, common in many species.
unknown locality, cult. NJ 2864
photo Jacobsen
The limb of the spathe of C. jacobsenii is quite typical. The surface is rough with prominent protuberances, there is a distinct collar and the throat is red / yellow with fine red spots.
unknown locality, cult. NJ 2864
photo Jacobsen
Opened kettle
unknown locality, cult. NJ 2864
photo Jacobsen
       
The plant is rather difficult to grow on the long term, at now there are no cultivated specimens left in Europe.
unknown locality, cult. B 356
This plant is up to now regarded as C. jacobsenii. In emersed culture, C. jacobsenii is a small plant, the leaf blades around 5 cm long and 2 cm wide, dark green, marmorated, the lower side pale green to reddish.
unknown locality, cult. B 414
A close up of the limb of the spathe. Note the rough, irregular structure of the limb of the spathe, the clear collar and the dotted throat.
unknown locality, cult. B 414
Opened kettle
unknown locality, cult. B 414
       
In 1985 Jacobsen and Bogner collected in Central Sumatra a broad leafed plant with a limb of the spathe that is to be compared with C. jacobsenii (NJ 85-27). Today we see this plant as (or near to) C. scurrilis.
coll.and cult. NJ 85-27
photo Jacobsen
    Drawing of C. jacobsenii after NJ 2864 in De Wit (1990).
drawing Juliet Williamson
       

The plant is named after professor Niels Jacobsen, Denmark, who made very many contributions to the knowledge of Cryptocoryne.

Updated May 2008

Literature.

Arends, J.C., Bastmeijer J.D. & Jacobsen, N., 1982. Chromosome numbers and taxonomy in Cryptocoryne (Araceae).II. Nord.J.Bot. 2 : 453-463.
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. & J.Bogner, 1987. Die Cryptocorynen der Malaiischen Halbinsel (4.Teil, Schluss), Aqua-Planta 3-87 : 96-103 (+ cover).
Jacobsen, N., 1992. Die Kultur einiger schwieriger Cryptocoryne-Arten in Buchenlauberde, Aqua-Planta 1-92 : 18-25.
Wit, H.C.D.de, 1976. Drie nieuwe Cryptocroryne-soorten, Het Aquarium 46(7) : 177.
Wit, H.C.D.de, 1990. Aquarienpflanzen, 2. Auflage. Ulmer, Stuttgart. ISBN 3-8001-7185-6.