Dendrobium brevicaule

Dendrobium brevicaule Rolfe, Bull. Misc. Inform. Kew (1899) 110.

Type: East New Guinea, Central Province, Mt. Scratchley, 3700 m, X 1896, Giulianetti s.n. (holo K).

Suberect to pendulous, tufted to branching epiphyte, to 20(-30) cm long. Roots 1-2 mm diameter. Rhizome very short, or up to 5 cm long in branching forms, cylindrical. Pseudobulbs 0.4-10 (-12) by 0.15-0.9 cm, fusiform to cylindrical, with 1-5 leaves at apex. Leaves 1-9 by 0.2-1.2 cm, spreading to pendent, elliptic to linear, apex obtuse to acute, mucronate; sheaths warty. Inflorescences terminal on leafy stems, 1-3-flowered, subsessile; bracts ovate, funnel-shaped, apiculate to acuminate, warty. Flowers 2.8-5.8 cm long, pendulous on flaccid pedicels, usually widely opening, long lasting. Median sepal 10-20 by 4.5-9 mm, oblong-elliptic to subrhombic, keeled, obtuse to acute. Lateral sepals 25-50 by 5-13 mm, obliquely triangular-ovate, acute to acuminate or apiculate, sometimes conspicuously keeled (to 3.5 mm high near apex), keels spurred at base; basal fused part 4-13 mm long, subconical; mentum total length 14-34 mm, tip obtuse to bilobed. Petals 8-16 by 4-7 mm, elliptic to subspathulate, obtuse to acute or apiculate. Lip 23-45 by 3-7 mm, subtrilobate, linear-oblanceolate, adnate to column foot at base, upper margins incurved apex triangular-acute, usually slightly recurved, margins erose. Column 3.5-7.5 mm long; foot 14-34 mm long; anther 3-6 mm broad; pollinia 2-3.5 mm long. Ovary 5-winged or ribbed, sometimes the lateral 2 wings small; pedicel-ovary 25-65 mm long, usually flaccid. Fruit to 18.5 by 12 mm, ellipsoid.
(after Reeve & Woods, 1989).

Colours: Rhizome sheaths blackish at base. Leaves green sometimes suffused with purple. Flowers bright orange to orange-red, lip apex often more red (occasionally tinged purplish), anthers usually dark purplish to black.

Habitat: Epiphyte in alpine shrubberies and forest, or on Cyathea in grasslands, rarely terrestrial. Altitude 2900 to 4000 m.

Flowering time in the wild: Throughout the year.

Distribution: New Guinea.

Distribution in New Guinea: See under the subspecies.

Map: BREVIMAP.JPG [Dendrobium brevicaule Rolfe, distribution map, redrawn from T.M. Reeve & P.J.B. Woods, Notes Roy. Bot. Gard. Edinburgh 46 (1989) 283, map 2.]

Notes: Dendrobium brevicaule is a spectacular orange-flowered subalpine species. It differs from the similar Dendrobium dekockii mainly in its larger size and in having a blackish anther cap.

Cultivation: Unfortunately, both D. brevicaule and D. dekockii are very difficult to keep in cultivation as they require strong light yet are intolerant to the high temperatures this inevitably causes in a greenhouse.


Key to the subspecies:

1a Plants tufted with stout crowded stems (usually epiphytic on tree ferns); pseudobulbs mostly over 0.5 cm diam.; leaves about elliptic, mostly over 0.7 cm broad ... Dendrobium brevicaule subsp. brevicaule
1b Plants tufted or branching; pseudobulbs less than 0.5 cm diam.; leaves usually linear to lanceolate, mostly less than 0.7 cm broad ... 2.

2a Lateral sepals not conspicuously keeled, keels less than 1 mm high ... Dendrobium brevicaule subsp. calcarium
2b Lateral sepals conspicuously keeled, keels over 1.5 mm high ... Dendrobium brevicaule subsp. pentagonum.


Dendrobium brevicaule Rolfe subsp. brevicaule.

Subsp. brevicaule is recognised by its strongly tufted habit, with no rhizomes; pseudobulbs 1-4 by 0.4-0.9 cm; leaves 1-9 by 0.6-1.2 cm, elliptic; flowers 3.85-8 cm long; lateral sepals without keels or only slightly crested.

Colours: Flowers brilliant orange.

Habitat: Epiphyte, almost exclusively on Cyathea species, in high alpine grasslands. Altitude 3350 to 3800 m.

Flowering time in the wild: February, June to August.

Distribution in New Guinea: Papua New Guinea (Central Province: Mt. Strong, Mt. St Mary, Mt. Dickson, Mt. Albert Edward, Mt. Scratchley, Mt. Victoria).

Notes: Subsp. brevicaule is a very high altitude race of the species and occurs on most of the high mountains of the Central Province of Papua New Guinea, growing almost exclusively on tree ferns in the alpine grasslands. Brass, in a field note on his specimen from Mt. Albert Edward, records it as an epiphyte on Dacrydium also.


Dendrobium brevicaule Rolfe subsp. calcarium (J.J.Sm.) T.M.Reeve & P.Woods, Notes Roy. Bot. Gard. Edinburgh (1989, publ. 1990) 184.

Basionym: Dendrobium calcarium J.J.Sm.

Subsp. calcarium is distinguished from subsp. brevicaule by its narrower pseudobulbs 0.4-12 by 0.15-0.5 cm, and usually narrower linear to lanceolate leaves 1-8 by 0.2-0.7(-1)cm. The flowers are 2.8-4.5 cm long with lateral sepals sometimes crested, keels less than 1 mm high.

Colours: The flowers are a brilliant orange to orange-red with the lip sometimes red.

Habitat: Epiphyte in alpine shrubberies and forest margins, rarely terrestrial. Altitude 2900 to 3650 m.

Flowering time in the wild: Throughout the year.

Distribution in New Guinea: Papua (Mt. Carstenz, Mt. Wilhelmina, Mt. Goliath, Mt. Antares); Papua New Guinea (Star Mountains, Mt. Iambari, Mt. Timtongopip, Mt. Ialibu, Mt. Giluwe, Mt. Hagen, Mt. Kigum, Mt. Wilhelm complex, Mt. Kerigomna).

Notes: Subsp. calcarium is the most widespread of the three subspecies and occurs from Mt. Carstenz in the west to Mt. Kerigomna (near Goroka) in the east.

This subspecies is quite a variable one. The type of Dendrobium calcarium, as well as most of the specimens from the Star Mountains area, are more narrow-leaved than those from Mt. Carstenz and Mt. Wilhelmina in the west as well as populations to the east. However, further collecting over a wider area, particularly in West New Guinea, and study of the various populations are required before any further infraspecific subdivision is contemplated.

T.M.Reeve & P.Woods (1989) were hesitant at first to make any division in Dendrobium brevicaule at all: their main concern being to carefully delineate the species. But when it was found that a fairly watertight key could be constructed, and the three entities showed reasonable geographical replacement, it was decided to divide this complex species into three subspecies.

Subsp. brevicaule and pentagonum are more uniform, whereas subsp. calcarium at present contains everything that was left, and is not quite as homogeneous. The size of the crests or keels on the sepals of this subspecies is quite variable and some forms have none at all. Others have recognizable crests, but they are all less than 1 mm high and clearly distinguished from the very conspicuous keels to be found on the lateral sepals of subsp. pentagonum. Like other subspecies of Dendrobium brevicaule these alpine subjects are quite difficult to cultivate. Whilst plants in the wild are tolerant of a large temperature range in the day (0-25 º C), Dendrobium brevicaule is subject to very low night temperatures, often near freezing point. At this altitude, the night relative humidity is 100% or almost so throughout the year.


Dendrobium brevicaule Rolfe subsp. pentagonum (Kraenzl.) T.M.Reeve & P.Woods, Notes Roy. Bot. Gard. Edinburgh (1989, publ. 1990) 186.

Basionym: Dendrobium pentagonum Kraenzl.

Subsp. pentagonum is distinguished from subsp. brevicaule by the conspicuously crested lateral sepals, the keels 2-3.5 mm high near apex, sometimes spurred at base. Pseudobulbs 1-12 by 0.15-0.4 cm, cylindrical. Leaves 2-8 by 0.2-0.5 cm, linear to lanceolate. Flowers 2.8-4.5 cm long.

Colours: The flowers are brilliant orange with the typical purplish-black anther caps.

Habitat: Epiphyte in alpine shrubberies. Altitude 3000 to 3600m.

Flowering time in the wild: Throughout the year.

Distribution in New Guinea: Papua New Guinea (Eastern Highlands Province, Morobe Province, (incl. Saruwaged Mountains), Central Province, Milne Bay Province).

Notes: This subspecies is known so far only from five mountains in the eastern part of New Guinea. On Mt. Albert Edward two subspecies are found: subsp. pentagonum grows in the Murray Pass area at 3000-3200m, whilst subsp. brevicaule occurs nearer the summit at 3400-3800m.

Subsp. pentagonum is readily recognizable by the very large keels, up to 3.5 mm high, on the outside of the lateral sepals.

In common with subsp. calcarium, the vegetative form of subsp. pentagonum varies considerably depending upon the degree of exposure to the sun, but generally it has a more lax, branched, pendulous habit.

The type of this subspecies is still extant at Hamburg, making the selection of a neotype as proposed by Reeve & Woods superfluous.

(largely after Reeve & Woods, 1989)