Cryptocoryne yujii Bastmeijer (Araceae),
a new species from Sarawak

Jan D. Bastmeijer, Emmen, The Netherlands
Aqua-Planta 27: 145-146

Summary Cryptocoryne yujii is a new species from the Sibu region in Sarawak, where it has been found north and south of the main Rajang River. It is characterized by an elongated, twisted spathe limb with a distinct dark purple collar and a white, irregular rugose inner surface. The leaves reach a length of 40 cm, the petiole and the upper side of the blade are bright green, the lower side somewhat paler, the blade is cordate and has an acute apex.

Description Cryptocoryne yujii Bastmeijer, (Araceae), eine neue Art aus Sarawak. - Aqua-Planta 27: 145-146 (2002). Rhizome ca. 5 mm in diameter, runners up to 30 cm long and ca. 2 mm in diameter. Leaves 15-40 cm long; petiole 9-28 cm long and 3-5 mm in diameter, bright green, sheeth 4-7 cm long. Leaf blade ovate, base cordate and apex acute, 6-12 cm long and 3-7 cm wide, bright green on the upper side and somewhat paler on the lower side, smooth to somewhat bullate, surface rough, especially the lower side. Cataphylls ca. 6 cm long, bright green. Peduncle rather long, 3-10 cm, white. Spathe 15-20 cm long, outside white; kettle narrow, 2-3 cm long (proportionally length to width 3.8 : 1), inside completely white; tube 3-5 cm long; spathe limb 8-12 cm long, elongate, twisted, somewhat forward bent, inner surface of the limb irregularly rugose, white, collar distinct, throat narrow, dark purple and slightly spotted near the tube. Female flowers 5-7 in one circle, carpels and styles greenish, rough; styles outwards bent; stigmas elliptical, with a purple border; olfactory bodies irregularly rounded, whitish; male flowers 30-40, with a purple border around the thecae; naked part of the spadix between the female and the male flowers white; flap over the male flowers white. Syncarpium ovate. Chromosome number 2n=34 (voucher at C).

Type: Sarawak, Sg. Nibong, southeast of Sibu, 26th October 2002, Yuji Sasaki no. M-SINN (L holotype, SING isotype).

Distribution Cryptocoryne yujii is found in several streams, both south and north of the main Batang Rajang river near Sibu.

Additional collections Yuji Sasaki no. M-SINN, Sarawak, southeast of Sibu, Sg. Nibong, 6th August 2002 (L, SING); J. Bastmeijer 980, Sg. Nibong, 27 August 2002 (K).

Ecology Cryptocoryne yujii grows on the banks and in the streams in at times somewhat cloudy water.

Notes Cryptocoryne yujii is distinct from other species by the colour and shape of the spathe, the white, rugose surface of the limb, the distinct purple collar and throat together with the narrow, elongate kettle. It is rather surprising that this new species has not been observed before, as western Sarawak is the most collected region of Borneo.

Etymology The plant is named after the collector, Mr. Yuji Sasaki, from Rayon Vert Aquarium in Japan. There is a great interest in Japan for keeping aquaria and growing tropical plants. Yuji Sasaki has for the last five years traveled a lot to study the habitats of Cryptocoryne and he has greatly contributed to the knowledge of the Cryptocoryne in Sarawak and Kalimantan (Borneo).

Acknowledgements I would like to thank Mrs. Anne-Marie Ramsdal for making the chromosome count, and Mrs. Charlotte Schoemacker and Mr. Helmut Roessler for translating the Latin diagnosis, as well as Mr. Niels Jacobsen and Mr. Yuji Sasaki for fruitful discussions.