2n = 38

2n = 38

2n = 38

2n = 38

2n = 38

Small perennial evergreen epiphyte, forming branched leafy often tangled tufts (2–)3–6 (–8) cm diam., with many tangled or spreading, white to brown, cord-like roots to 45 cm × 2 mm, adhering to surface of bark or rock. Stems 20–40 mm long, often shorter, horizontal or inclined, supporting (2–)3–6(–8) flat or channelled live leaves above a ± dry lower part covered with old imbricating leaf bases and withered persistent peduncles. Leaves (1.0-)3-5(-7) × 0.5–1.5(–2) cm, elliptic to lanceolate with acute to acuminate, often twisted tips; crowded alternate, imbricate at base and arranged distichously; green or yellowish green, frequently purple spotted, glabrous, thick, leathery. Racemes 1 or more per stem each year, to 50 mm long, arising from among leaves; stout and stiff, green or yellowish green streaked with purple, turning pink with age, bearing (1–)2–6(–10) alternate slightly fragrant flowers, 4–5 mm across, on pedicels 2–3 mm long, each subtended by a narrowly ovate to lanceolate membranous bract c. 2 mm long. Flowers at first yellowish green, often flecked with purple on the outside, becoming more yellow at anthesis, even more so when dried. Ovary 2.5–3 mm long, linear oblong, straight. Sepals and petals subequal, ± fleshy, oblong obtuse, slightly cucullate at tips; spreading fairly widely but projected forwards and inwards to form a cup. Dorsal sepal 3.5–4.0 × 1.5 mm; lateral sepals slightly shorter; petals 2.5– 3.0 × 1.5 mm. Labellum c. 2.0 × 1.8 mm, projected forwards, immobile, concave, channelled; apex thickened, fleshy, slightly emarginate and folded inwards, clear yellow; 2 green, raised, nectariferous swellings at base; lacking distal lamina calli. Column 1.5 × 1.0 mm, inclined slightly forwards, cylindrical, yellowish green. Anther 0.7 mm long, with a prominent sharply pointed rostellum 0.3 mm long; anther cap 0.7 mm across, doubly convex, broadly ovate acute, creamy yellow. Stigma 0.4 mm across, concave, deeply sunken. Pollinarium consisting of 4, globular to obovoid, yellow, mealy pollinia in 2 unequal pairs; stipe 2-fid, viscidium flat, ± shield-shaped. Capsule to 15 × 5 mm, fusiform, yellowish green and purple spotted, containing numerous seeds c. 0.5 × 0.1 mm, with intermixed twisted hygroscopic hairs 4–5 mm long. FLOWERING: Plants of D. flavus flower annually beginning in October and continuing into November. Floral induction seems to occur in the summer preceding flowering, and new racemes appear in April and grow steadily through the winter. Very small plants with two leaves, each c. 1.0 cm long, are capable of flowering. Although the flowers are structurally adapted for insect pollination, they are probably self-pollinating as well, since a high proportion of flowers on cultivated plants form capsules when screened from insects. D. adversus has a similar pattern of floral induction, flowering, and seed set. FRUITING: Capsules are fully formed from late December to January, mature slowly, and begin to dehisce about July, by which time new racemes are well advanced. Seed release occurs over a long period and is assisted by the movement of hygroscopic hairs within the capsules. Although some seed is undoubtedly dispersed more widely by wind, much is shed close to parent plants, giving rise to many seedlings horizontally along branches and vertically down stems. This may also reflect the availability of fungal symbionts necessary for germination and seedling establishment. Old capsules are long-persistent; peduncles or raceme axes even longer.

D. adverso similis differt autem statura minore, foliis tenuioribus magis coriaceis ellipticis vel lanceolatis acutis saepe maculatis, floribus flavis, labello a distalibus laminae callibus destituto, capsulis saepe maculatis, et chromosomatum numero 2n = 38, diploideo.