The biology of Epipogium roseum (D. Don) Lindl

Epipogium roseum is a tropical, holosaprophytic orchid; it lacks chlorophyll, and its colour on the whole is pale yellow, occasionally somewhat brown. The flowers are also pale yellow, sometimes with pink dots on the lip. The flowering plant consists of a tuber and an inflorescence, roots are lacking. When the flowering is over and the fruits have dehisced, the plant dies. It grows in densely shaded places, rich in humus, in virgin forests, secondary woods, and in bamboo wildernesses. The plant is of frequent occurrence in the so-called forest-garden in the Botanic Gardens at Buitenzorg and in the lower parts of the mountain forest near Tjibodas, up to an altitude of about 1500 m above sea-level. For many years this plant has held my attention. Burgeff used the photographs I made up to 1928 and part of the material I collected in his publication (1932, p. 77). Groom (1895—97, p. 149) and Burgeff gave extensive descriptions of the anatomy and development, so that I may be brief as to these points. The tuber is flattened dorsi-ventrally, otherwise more or less cylindrical, and may be from 3 to 8 cm long, the transverse section being from 1 tot 2½ cm. On the outer side this tuber is ringed, but the bracts have developed but slightly. At the apical end develops a large bud, from which will grow up the inflorescence. The latter rises above the ground with a nodding top, and in this stage (see Fig. 1) the plant is very similar to a Monotropa Hypopitys L. that has just come up. Because of this nodding top Blume (Bijdr. 1825, p. 416) called it Galera nutans.