2n = 36

2n = 36

2n = 36

Summer-green, terrestrial, glabrous, tuberous herb forming extensive colonies. Leaf solitary, firm and fleshy, sessile; usually spreading and held flat to the ground surface; lamina 18- 40 × 15-35 mm at widest point, bluntly wedgeshaped to ovate-oblong, sometimes pandurate, apiculate at tip, with apiculus decurved, rounded and cordate at base; midrib slightly grooved above, flat beneath; leaf colour dull green above with purple spots on margins, on midrib, or overall, silvery and pellucid beneath. Flowers usually solitary, rarely two, 10-15 mm long, generally green throughout except for labellum tube, dominated by the labellum and filiform petals and lateral sepals, on a peduncle 3—5 × 1.5—2 mm, usually purple streaked. Ovary 5— 8 × 2-4 mm, green, sometimes streaked with purple, curved, subtended by two unequal floral bracts, the smaller vestigial to 3 mm long, subulate, the larger 6—10 × 3—5 mm, narrowly ovate-lanceolate, green, equalling the ovary, curved. Dorsal sepal 15— 20 × 5—8 mm, exceeding the labellum, lanceolate in outline when flattened, concave, cucullate and arching over labellum tube, with apex upturned; green, slightly diffused with purple on veins. Lateral sepals 50-70 × 0.5-1.0 mm at widest point; filiform, greatly exceeding labellum; green, sometimes flecked with purple; suberect to erect and spreading; channelled, twisted and connivent at base. Petals 40—60 × 0.5— 1.0 mm at widest point, usually shorter than lateral sepals; filiform, greatly exceeding labellum; projecting forwards and outwards; channelled, auriculate on the base of the column. Auricles short, projecting downwards and forwards, with apertures 1.0— 1.5 mm across. Labellum usually green except for labellum tube and upper margins of lamina which are often purple-flushed or streaked; labellum tube 8—10 mm long, erect at first then doubly deflexed through 90—180° and expanding into the lamina; lamina 6—8 × 8—10 mm, broadly ovate; upper margins folded inwards and overlapping; lower surface spreading, deflexed against ovary, rounded or obtuse with slightly erose margins and a median apiculus; inner surface with scattered minute papillae, veins ridged; throat of labellum tube notched, barely over half-way on lamina. Column 2.5—3 mm long, broadest and ridged at base, inclined backwards, minutely winged. Stigma shield-shaped, c. 0.7 mm across, concave, margins minutely lobed and fimbriate. Anther c. 1.0 mm, obtuse, crested, margins papillate; pollinia 4, united in pairs, c. 0.6 × 0.4 mm, oblong, mealy, yellow; viscidium rounded, concave, white at first later greenish-brown, c. 0.5 mm across. Capsule 10-16 × 4—6 mm, elliptic, at first green later brown, on greatly elongated peduncle. Tuberoids globose to ellipsoid on extended roots. FLOWERING: September to October. Plants in the wild and in cultivation flower annually though with varying intensity. The flowers of C. papa are principally or entirely insect-pollinated, presumably by fungus gnats. It is of interest that gnats (Mycetophila spp.) observed visiting flowers of C. iridescens grown in cultivation clearly avoided flowers of C. papa grown alongside (Fuller 1994; B. P. J. Molloy pers. obs.). FRUITING: September to November. Mature capsules borne on greatly elongated peduncles develop rapidly after fertilisation, producing abundant seed which is dispersed by wind, water, or gravity.

C. rivulari similis a quo foliis grandioribus retuse cuneatis, floribus grandioribus praecipue viridibus, sepalo dorsali latiore concavo, labelloque duplo deflexo expanso in laminam distaliter explicatam rotundatam apiculatam differt.