Dendrobium sens. lat., as recognised by the Australian Plant Census [CHAH (2018), accessed 26 September 2022], includes the following descriptions from Jones (2021): Australorchis Brieger: Epiphytic orchids with short, swollen pseudobulbs connected by thin rhizomes. Pseudobulbs thick, conical, with 1 to a few internodes. Leaves 1-2, terminal on pseudobulb, narrow, thin. Inflorescence racemose, multiflowered, arising in upper leaf axil. Sepals and petals spreading or cupped. Bases of lateral sepals fused with margins of column foot. Labellum attached to apex of column foot. Labellum lamina 3-lobed. Callus with keels or ridges. Ceraia Lour.: Epiphytic or lithophytic orchids. Pseudobulbs with a thin basal section, expanded middle section (can be flat or swollen), tapering to a slender upper section that is leafy with a leafless apical region where flowers are borne. Alternatively, plants have an untidy appearance with freely branching, erect or pendulous stems bearing alternate, flattened, pointed leaves with a thin, leafless portion where flowers arise. Flowers short-lived, arising singly at sporadic intervals from long-lived nodes. Sepals larger than petals or of similar size. Bases of lateral sepals fused to column foot to form mentum. Labellum 3-lobed with midlobe often notched; some species also have a separate swollen part at the base. Coelandria Fitzg.: Epiphytes or lithophytes with very short rhizomes anchored by roots that arise from nodes at the base of the pseudobulb. Pseudobulbs elongated, hard, cane-like, thickened in the middle, nodes irregularly swollen, leafy in the distal half. Leaves lasting 1 season, thin, flat, without any channel or groove, much longer than wide, basally sheathing, apex unequally notched. Racemes short, condensed, arising from the upper nodes of a pseudobulb. Flowers long-lasting, crowded, thick-textured, unscented. Perianth segments very thick and fleshy. Lateral sepal bases fused with the column foot. Sepals and petals of similar length. Petals narrower than the sepals. Labellum stiffly attached to the apex of the column foot. Labellum lamina unlobed, more or less tubular, with a very thick upturned apex and a long basal spur (Source: Jones, Hopley & Duffy 2010). Conostalix (Kraenzl.) Brieger: Terrestrial clumping orchids with coarse roots. Stems thin and cane-like, wiry, leafy. Leaves axillary, sessile, thin-textured, arising alternately along stems at sharp angle with long sheathing base that covers two nodes. Flowers arising singly or in pairs from node; buds bursting through leaf sheath on opposite side of leaf. Flowers closed or not opening widely. Sepals much wider than petals. Margins of lateral sepals fused to column foot. Labellum 3-lobed, its base fused to column foot to form an elongated spur. Column with strongly reflexed column foot. Davejonesia M.A.Clem.: Small epiphytic orchids with creeping rhizomes that form strands or dense mats. Pseudobulbs absent. Leaves thick, fleshy, arranged alternately along stems, not grooved or channelled. Flowers small, borne singly from rhizome near base of recently mature leaf, widely opening, with red stripes and yellow or orange labellum. Sepals much broader than petals. Bases of lateral sepals fused with column foot. Labellum attached to apex of column foot. Labellum lamina obscurely lobed, thick and fleshy. Dendrobium Sw.: Epiphytic or lithophytic orchids with long, narrow pseudobulbs that are leafy throughout in the first year, but leaves are quickly shed as the pseudobulb matures, usually within 12 months of emerging. Leaves sessile, dehiscing above sheathing base. Inflorescences racemose, short, arising from lateral nodes, never from terminal nodes. Flowers generally colourful. Sepals and petals of similar size. Bases of lateral sepals fused to column foot to form mentum. Petals free. Labellum 3-lobed but lateral lobes often poorly developed and obscure; ventral surface with small papillae or hairs; basal claw fused to margins of column foot to form nectary. Column foot well developed. Durabaculum M.A.Clem. & D.L.Jones: Plants variable, all with hard pseudobulbs; pseudobulbs cylindrical, leafy towards apex, leaves lasting about 12 months and shedding quickly as climatic extremes become severe; alternatively pseudobulbs long, cane-like, cylindrical or spindle-shaped, with long-lasting, fleshy or leathery leaves on middle and upper nodes; or pseudobulbs short to elongated, onion-shaped, with thick, channelled leaves (nearly cylindrical) from apical nodes. Racemes long, slender, arising from apical nodes. Flowers colourful and long-lasting, sometimes with thick, leathery segments. Petals significantly larger than sepals (sometimes very broad), usually longer. Petals and sepals sometimes with indented or wavy margins; often, but not always, strongly twisted. Lateral sepals fused with margins of column foot. Labellum 3-lobed (sometimes obscurely lobed), hinged (sometimes stiffly) to column foot, adorned with prominent ridges or keels and occasionally colourful dark lines. Sayeria Kraenzl.: Clumping epiphytic orchids. Pseudobulbs hard, swollen, often stalked towards base. Leaves apical on pseudobulbs, without obvious sheathing base. Inflorescence racemose, arising from upper axillary node. Flowers clustered towards top of long peduncle, colourful, on long pedicels. Sepals much broader than petals. Bases of lateral sepals fused to column foot. Labellum prominent, hinged to apex of column foot. Labellum lamina 3-lobed. Stilbophyllum D.L.Jones & M.A.Clem.: Epiphytic or lithophytic orchid with creeping habit, usually forming dense mats on host. Pseudobulbs vestigial and leaves joined together by short stems. Leaves thick, fleshy, deeply concave, ventral surface sparkling from intense concentration of silica spicules, basal sunken area with prominent papery bract. Stalkless upward-or outward-facing flowers arise singly from floral meristem in basal bract. Dorsal sepal free. Lateral sepals fused to margins of column foot and united in front. Labellum stiffly attached to apex of the column foot. Labellum lamina obscurely 3-lobed, curved, channelled. midlobe fleshy. Column short with relatively long basal foot. Thelychiton Endl.: Epiphytic or lithophytic clumping orchids. Pseudobulbs cylindrical, tapered, fusiform, or tetragonal. Leaves apical on pseudobulbs, without prominent sheathing base, few, thin-textured to thick and leathery. Inflorescence racemose, arising from upper axillary nodes, multiflowered. Flowers resupinate, relatively large, often colourful. Dorsal sepal and petals free. Sepals broader than petals. Bases of lateral sepals fused with column foot. Labellum stiffly hinged to apex of column foot. Labellum lamina 3-lobed; lateral lobes often erect, flanking column. Callus of narrow parallel ridges, sometimes hairy. Column with prominent basal foot. Trachyrhizum (Schltr.) Brieger: Epiphytic clumping orchids. Pseudobulbs widely spaced on rhizomes, slender, leafy in upper half. Leaves oppositely arranged, with large basal sheath. Inflorescence racemose, few-flowered, arising from lateral buds on pseudobulb opposite a leaf. Flowers generally remaining cupped, with thick, waxy segments. Sepals much broader than petals. Bases of lateral sepals fused with margins of column foot. Labellum hinged to apex of column foot. Labellum lamina 3-lobed. Callus with keels or ridges. Column with long basal foot.
More
Herbs epiphytic, lithophytic, or less often terrestrial, polymorphic, deciduous or evergreen. Stems either: 1) rhizomatous, 2) erect and many noded, 3) erect and 1-noded or several noded from a many-noded rhizome, or 4) without a rhizome, new stems of many nodes arising from base of old ones; 1 or 2(-500) cm, tough or fleshy, 1 to several internodes swollen at or near base or along entire length to form canelike pseudobulbs, ± covered with sheathing leaf bases and cataphylls, often turning yellow when dried. Leaves 1 to many, alternate, apical or distichous along stem, linear, lanceolate, oblong, or ovate, sometimes subterete or terete, papery to rigid and leathery, sometimes with black or brown trichomes especially on sheath, base articulate and often with clasping sheaths, apex usually 2-lobed or emarginate. Inflorescences lateral, generally distal, in some sections pseudoterminal, 1-to many flowered, usually racemose, erect, horizontal, or pendulous; floral bracts usually insignificant. Flowers extremely variable in color and shape, often showy, very small to large, resupinate or not resupinate, usually spreading, ephemeral or long-lived. Sepals similar, free, short to filiform; lateral sepals adnate to elongated column foot and part of lip to form a mentum, 0.1-3 cm. Petals free, margin entire to fimbriate; lip entire to distinctly 3-lobed, base joined to column foot, sometimes narrowly clawed at base, sometimes forming a closed spur with lateral sepals to which it may be joined laterally for a short distance; disk with 1 to several keels, sometimes verrucose-papillose, calli rarely present, sometimes with a transverse basal ridge. Column short, stout; foot long, sometimes with a protuberance adaxially; apical stelidia obscure to distinct; viscidium present; pollinia 4 in appressed pairs, waxy, ovate or oblong, naked, i.e., without caudicles or stipes.
Infl. us. lateral, 1-∞-fld; floral bracts often very small. Per. us. large and showy; dorsal sepal uppermost, free; lateral sepals adnate to column-foot (forming a mentum); petals > or < sepals, us. thinner. Labellum ± 3-lobed, claw attached to end of column-foot, disc often longitudinally lamellate but rarely with calli. Column short, ± winged, foot long; anther terminal, operculate, incumbent, narrowly joined to column just below its apex, caducous, pollinia 4, ± waxy, without caudicles; stigma deeply concave, separated from anther by narrow transverse flap. Plants epiphytic or rupestral; growth sympodial; stems ± elongated, sts swollen into fleshy pseudobulbs. Lvs variously shaped, jointed to sheath. Genus of nearly 1,000 spp. from India and Ceylon to southern China and Japan, southwards through Malaya far into the Pacific and to Australia, the one N.Z. sp. endemic.
Home
