Species Information - Dendrobium brevicaule

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.
Flowers brilliant orange.
The flowers are a brilliant orange to orange-red with the lip sometimes red.
The flowers are brilliant orange with the typical purplish-black anther caps.

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

New Guinea.

See under the subspecies.
Papua New Guinea (Central ProvincePapua (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,

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.

Throughout the year.

• Family Orchidaceae
• Subfamily Epidendroideae
• Tribe Dendrobieae
• Subtribe Dendrobiinae
• Genus Dendrobium
• Section Calyptrochilus
• Species Dendrobium brevicaule

• Reeve, T.M. & P.J.B. Woods. 1990. Notes Roy. Bot. Gard. Edinburgh 46: 182, fig. 4 & 5, pl. 1 & 2.
• Royen, P. van. 1979. Alp. Fl. New Guinea 2: 433, fig. 150.

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

Dendrobium brevicaule plants in the wild are tolerant of a large temperature range in the day (0-25 degree Celcius), and are subject to very low night temperatures, often near freezing point. At that altitude the night relative humidity is 100% or almost that high throughout the year.


T.M.Reeve & P.Woods (1989) were hesitant at first to make any division in Dendrobium brevicaulel: their main concern was 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:

Dendrobium brevicaule subsp. brevicaule
Dendrobium brevicaule subsp. calcarium
Dendrobium brevicaule subsp. pentagonum


KEY TO THE SUBSPECIES OF DENDROBIUM BREVICAULE:

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.




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Dendrobium brevicaule Rolfe subsp. brevicaule.

Synonyms:

Pedilonum brevicaule (Rolfe) Rauschert, Feddes Repert. 94 (1983) 457.
Dendrobium cyatheicola P.Royen, Alp. Fl. New Guinea 2 (1979) 435, fig. 151 (= subsp. brevicaule).
- Type: Hartley 12913 (holo L, iso AMES, CANB, LAE).

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.

Subsp. brevicaule is a very high altitude form 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. In a field note on his specimen from Mt. Albert Edward where it occurs nearer the summit at 3400-3800m, Brass records it as an epiphyte on Dacrydium as well.

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

Synonyms:

Dendrobium calcarium J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 2, 2 (1911) 13; Nova Guinea 12, 1 (1913) 69, t. 18, fig. 55. Lectotype: (designated by van Royen 1979) West New Guinea, Mt. Goliath, 3250m, February 1911, de Kock IX (BO).
Pedilonum calcarium (J.J.Sm.) Rauschert, Feddes Repert. 94 (1983) 458.
Dendrobium aurantivinosum P.Royen, Alp. Fl. New Guinea 2 (1979) 449, fig. 156 (= subsp. calcarium).
- Type: NGF (Ridsdale & Galore).
Dendrobium montistellare P.Royen, Alp. Fl. New Guinea 2 (1979) 401, 404, fig. 139 (= subsp. calcarium).
- Type: Nicolas 5 a (holo L).
Dendrobium montistellare P.Royen f. albescens P.Royen, Alp. Fl. New Guinea 2 (1979) 404 (= subsp. calcarium).
- Type: ANU (Wheeler) 6117 (holo CANB, iso L, LAE).
Dendrobium quinquecristatum P.Royen, Alp. Fl. New Guinea 2 (1979) 446, fig. 155 (= subsp. calcarium).
- Type: ANU (Hope) 16147 (holo CANB).

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.

This subspecies is quite variable. The type of Dendrobium calcarium, as well as most of the specimens from the Star Mountains area, have narrower leaves than both those from Mt. Carstenz and Mt. Wilhelmina in the west and 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.

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 known so far only from five mountains in the eastern part of New Guinea.

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

Synonyms:

Dendrobium pentagonum Kraenzl., in Engl., Pflanzenr. IV. 50. II. B. 21 (1910) 128.
- Type: East New Guinea, Milne Bay Province, Mt. Dayman, 3000m, iii 1894, Armit s.n. (HBG).
Pedilonum pentagonum (Kraenzl.) Rauschert, Feddes Repert. 94 (1983) 462
?Dendrobium saruwagedicum Schltr., Repert. Spec. Nov. Regni Veg. 16 (1919) 217.
- Type: Keysser s.n. (X-1912, Saruwaged Mountains SE of Sattelberg, Mt. Bolan 4000 m) (holo B, lost)
?Pedilonum saruwagedicum (Schltr.) Rauschert, Feddes Repert. 94 (1983) 463.
Dendrobium teligerum P.Royen, Alp. Fl. New Guinea 2 (1979) 420, fig. 146, pl. 89 (= subsp. pentagonum).
- Type: NGF (Dockrill (Elworthy]) 7991 (holo L; iso LAE).
Dendrobium zaranense P.Royen, Alp. Fl. New Guinea 2 (1979) 441, fig. 153 (= subsp. pentagonum).
- Type: NGF (van Royen) 16176 (holo L; iso K, LAE)

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.

Subsp. pentagonum is readily recognizable by the very high 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 on 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)

Subsp. pentagonum grows on Mt. Albert Edward in the Murray Pass area at 3000-3200m, Subsp. brevicaule grows also on Mt. Albert Edward but at higher altitudes.

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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 no crest 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 plants are quite difficult to cultivate.