NEW GUINEA FIELD NOTE EXTRACTS

Neville H.S. Howcroft

In several past issues of the PNG Orchid Society Newsletter our editor has presented readers with useful descriptions of the orchid genera. By my estimation, which is based on recent accounts of name changes and new discoveries, there are some 140 genera occuring in New Guinea and adjacent islands. Many of these genera have been subdivided into sections and it is certain that some of these will be elevated to generic rank.

The division of genera into sections is based on plant habit and flower characters. Sectional differences are not always readily apparent to a person reading an orchid article which has only a photo or an illustration of a flower. Recognition of an orchid in the field or in cultivation at the generic and sectional level are the first steps towards identifying the species or recognising that one has found a new species.

In New Guinea some genera are so far only known to be represented by one species and therefore considered to be monospecific. Other genera, such as Bulbophyllum and Dendrobium, have a large number of species, requiring the genus to be split into sections. Where a genus might be considered monospecific some caution must be exercised as the genus may be represented in other adjacent countries by several more species. Where a genus such as Ridleyella Schltr. is represented by a single species, over the geographic range of the genus, there is no need to place the species in a section. However, should other species be discovered for this genus later on, and some of these have characters which make them somewhat more distinct than the first species, then there may be justification for the creation of two or more sections for better recognition. In this article some examples are given to demonstrate sectional differences in some orchid genera.

DETAILS

Bulbophyllum Thouars.

A number of species of this genus have already been illustrated in previous issues of the PNG Orchid Society's Newsletter. This genus, which may be epiphytic on trees or rocks, contains around 42 sections, some of which may be elevated to generic status in the future such as Cirrhopetalum.

Bulbophyllum nitidum Schltr.

This beautiful species, which is commonly found at high altitudes in New Guinea, belongs to the section Coelochilus Schltr. It is typical of the species in this section which bear single flowered inflorescences. The flowers are fairly large. The sepals are maroon and white and the labellum is maroon. The petals are white with maroon veins.

The distinguishing floral characters of this section are the long narrow lanceolate sepals and the long and broader fleshy labellum, which is often the most colourful part of the flower. The petals are typically small, but usually differ in shape between the species and are useful for identifying the species.

Species of this section occur from about 500 metres to the mist forests around 2,500 metres. The specimen illustrated here comes from the Gumi area near Bulolo in the Morobe Province.

Bulbophyllum macphersonii Rupp.

This Bulbophyllum is a member of the section Polyblepharon Schltr., the species bear single flowered inflorescences. The flowers are often small and they are characterized by their prominently displayed labellum which has eyelash-like hairs along its margins. Some species also have some glandular hairs. The sepals are usually bent backwards and the lateral ones are partly fused together along their lower margin, which gives the impression of a single sepal. The labellum is extremely mobile at the slightest movement of wind.

This tiny species occurs in North Queensland, Australia (Dockerill, 1969). The specimen illustrated here was found recently, by the present author, on Woodlark Island. It represents a new record for Papua New Guinea. The sepals are maroon to reddish brown, the petals are yellow with merging red, brown and maroon veins. The labellum is maroon and light yellow with grey hairs at the base near the lateral lobes. It appears to differ from the Australian species by having slightly broader leaves.

Members of this section occur from sealevel to around 2,500 metres altitude and very likely at higher altitudes.

Bulbophyllum macranthum Lindl.

According to Vermeulen (1991) in his treatment of the Bulbophyllum of Borneo, this species belong to the section Sestochilus (Breda) Benth and Hook. f. in which he includes a number of other species that do not appear to be closely related to the likes of B. macranthum.

The species in this section are similar in plant habit. The pseudobulbs are short, oblong, sub-cylindrical or ovoid. The rhizomes are long, often thick, with the fibrous remains of the sheaths at each internode and at the base of the pseudobulb. The flowers of B. macranthum are white to light yellow with pink and maroon markings. The labellum is yellow.

All but one of the New Guinea species (B. guttatum Schltr.) have flowers that are presented either with the lateral sepals on top (Fig. 3) or with the flower in a face upwards position (Fig 4). The inflorescences are normally single flowered on a very short peduncle. Bulbophyllum tortum Schltr. is the only species of the New Guinea representatives known to produce two flowers. This event is considered unusual and rare for this species which mostly produces a single flower. The flowers on all the New Guinea species are fleshy and have a glossy appearance. They all produce a strong sweet perfume that attracts various species of fruit fly of the genus Daccus.

Smith places this species and its relatives in the section Stenochilus J.J. Sm. According to Vermeulen this section does not appear to have a type species described upon which the sections should be established. Generally speaking there is a further need for revision within the section as treated by Vermeulen.

The specimen illustrated here comes from the coastal region near Lae in the Morobe Province.

Bulbophyllum emiliorum Ames et Quisumbing

Another representative of section Sestochilus this species was recently described as a new record for Papua New Guinea (Howcroft, 1992). This species is illustrated here as an example in the section where the flower is presented in the face-upward position. Other species with this habit are B. bailyii, B. macranthoides Krzl., B. tortum Schltr.and B.gjelleruppii J.J.Sm.

Bulbophyllum guttatum Schltr.

This attractive species, with red spotted yellow-white petals and sepals and a deep red labellum, is included by Schlechter with B. grandifolium Schltr, B. hahlianum Schltr., B. werneri Schltr. and B. tortum Schltr. in the section Sestochilus . The differences between this and the other species mentioned above are associated with the way the flower presents itself and the shape of the floral parts. The pseudobulb is also different being much smaller and cylindrical compared to the larger and thicker pseudobulbs of the other species mentioned above.

The flower is in a porrect position on the plant (as illustrated) and neither in the reverse position with the lateral sepals on the top, nor in the face-up position; In the other species the labella are relatively long, narrow and more or less glabrous, whereas in B. guttatum the labellum is relatively large, short, broad, with a pustular surface. The final difference is to be seen in the pronounced lateral stelidia of the column projecting down towards the column which are not seen in above mentioned species. This characteristic of the column is identical to that found in B. cornutum (Bl.) Rchb.f. from Borneo and B. refractilingue J.J.Sm. which has a multiflowered inflorescence.

The specimen illustrated here was collected in the region of the upper reaches of the Sepik River close to the junction of the August River at an altitude around 200 metres.

Calanthe R. Brown

This terrestrial genus has many beautiful species. Very few of the New Guinea species are known to be in cultivation outside of Botanic gardens. There are 6 sections recognised in New Guinea. These are Eu-preptanthe, Caulodes, Rhodochilus, Calothrysus, Styloglossum and Aceratochilus.

Three of these sections are illustrated here by a representative species.

Calanthe longifolia Schltr.

This mountain species belongs to the section Styloglossum which does not appear to be very common in private collections. The main colours are white and yellow and the inflorescence and flowers are glabrous. The flowers of this particular species are white. There are several close relatives to this species. The main differences to look for are in the characters of the labellum. This species has two ridges on the base of the midlobe of the labellum which is lacking in its closest relatives and the lateral lobes are not as pronounced as in the others.

The plant illustrated here comes from the Araucaria and Oak forests at Bulolo in the Morobe Province.

Calanthe rhodochila Schltr.

A high mountain zone species representative of the section Rhodochila. The plant is short and not much more than 40 cm tall with narrow leaves. It possesses a very distinctive inflorescence, glabrous in appearance and with long overlapping floral bracts. The the small light green flowers with their striking red labellum, present themselves between the bracts.

The species illustrated was collected in logged over forest at Wara Kum near Mt. Hagen at an altitude of around 2,500 metres.

Calanthe cremeo-virida J.J. Wood

This fairly common species found in the low and mid-montane forests is placed in the section Calothrysus to which the well known Calanthe triplicata is also placed. This species and its relatives are moderately to very tall growing species with flowers that have pubescent sepals. The peduncle and the rhachis are usually minutely pubescent. This species has green sepals and light yellow green petals and labellum. With the inflorescence the plant can attain heights of around 1 metre.

The illlustrated specimen was collected from Araucaria forest at Bulolo around 1,300 metres altitude. It is also very common in parts of Oak forests.

Dendrobium Swartz.

This popular genus contains species which are generally epiphytic, but may be found growing terrestrially on exposed soil, in peat or on rock faces. In New Guinea the genus is represented by around 36 sections.

In previous Newsletters a number of species have been illustrated that are representatives of the sections Aporum, Latouria, Oxyglossum, Rhizobium, Rhopalanthe and Spathulata ( Bandisch, 1992; Howcroft, 1992; O'Byrne, 1991; Omerod, 1992; Spence, 1992). Two other sections, Euphlebium and Trachyrhyzum are illustrated here. Both are found in New Guinea and the last section is also represented in Australia.

Dendrobium coeloglossum Schltr.

One of several epiphytic species in the section Euphlebium in New Guinea. The section also extends as far as Malaysia. The pseudobulbs of the plants in this section are characteristically four to five angled, somewhat clavate they are attenuate and terete towards the base. The stems have a number of internodes and with few or no sheaths. Apically there are one to two leaves. Flowers are produced singly or in pairs from depressed nodes below the leaves. They are large, fleshy and short lived.

The species illustrated here has attractive yellow to cream coloured flowers. The margin of the labellum and the ridges and keels of the lip are edged in brown. The plant was collected from a beach tree near Dregerhafen, Morobe Province.

Dendrobium vandoides Schltr.

As the name suggests, this erect epiphytic orchid looks very much like a strap-leaf Vanda. The species is one of many that have been placed in the section Grastidium.

The species in the section are characterized by their cane-like, multi-internode, stems. These usually have many leaves. The leaves may be long and narrow or ligulate-lanceolate. The inflorescence is usually two-flowered (occasionally three-flowered) and it is produced laterally from a flat sheath.

The flowers are always short lived, lasting no more than two days. They are quite variable in form and possibly when more is known about the species it may be neccessary to separate some species into new sections. Some species flowers emit very pleasant perfumes.

The species illustrated here produced pairs of flowers with cream coloured tepals with broad dark red and maroon blotches.The labellum was white with some orange partches on the disc and on the column foot. The species appears to be variable in plant size and iin the size and colour of the flowers over it known range in New Guinea.

The plant was collected from a Leucaena shade tree, at around 200 metres altitude, in the Warangoi region of the Gazelle Peninsula of East New Britain (Howcroft, 1992).

Dendrobium villosipes J.J.Sm.

This orchid is very close to D. prostheciglossum Schltr. var. obtusilobum Schltr. It was originally discribed from Irian Jayan material. The plant is terrestrial and it is comprised of several slender terete canes up to 1 m tall with short rhizomes and with rough, papillose root. The plants produce leathery, oblong-lanceolate leaves along the stems. The inflorescence is short more or less porrect to arched and carrying 4 to 6 or more glossy, brown and green fleshy flowers with a yellowish white labellum.

The species has been previously found in Papua New Guinea by Tom Reeves who established the Laiagam Orchid collections. The plant illustrtade here was collected on Mt Kaindi around 2,500 metres altitude on old mine dumps at Edie creek, near Wau township. Schlechter's variety and Smith's species may prove to be conspecific.

The section has around six species in New Guinea and one in some of the adjacent islands. One other species is found in Australia.

Dipodium R. Brown

This saprophytic genus is represented by some 25 species over its geographic range (Jones 1988). There are two species in New Guinea, the terrestrial Dipodium elatum J.J.Smith and the semi-epiphytic Dipodium pictum (Lindley) Reichb. f.. The latter was formerly known as Dipodium pandanum Bailey. (Lewis and Cribb, 1991)

Dipodium elatum J.J.Sm.

The species belongs to the section Eu-Dipodium. All the species in this section are leafless. They are usually found in open savannah.

This section is well represented in Australia (Jones 199 ) and one species is found in New Caledonia and in the Solomon Islands. Several of these look like Hyacinths and are referred to as the Hyacinth orchids in Australia. The flowers of this New Guinea species are white with purple spots and with pink and purple markings on the labellum..

The illustration here is by Dr. J. Dodd who found the plant on the University ground at Port Moresby.

Dipodium pictum (Lindl.) Reichb.f.

The second species starts its life on the ground or in rotten logs in secondary regrowth and inside light canopied tropical forest. From this position it starts to climb rocks, saplings and tall trees. Eventually the lower portion of the stem dies off leaving the plant growing lke an epiphyte. The growth habit appears monopodial(Fig.10). Injury to the appex will encourage side growths and the development of two or more growths. This species belongs to the section Wailesia. It is a wide spread species occurring in Northern Australia, a number of the Pacific Islands, through to the Malay Peninsula. It is possible that a second Australian species, Dipodium ensifolium, also belongs to this section.

The flowers of this species have creamy white sepals and petals with maroon blotches and the labellum is white with pnk and violet markings. The specimen illustrated was collected in secondary regrowth forest at Bulolo in the Morobe Province.

Habenaria Willd.

Schlechter, in his treatment of this genus lists six sections. This included Peristylus which is now regarded a distinct genus. The other sections are Plantagineae, Acuiferae, Chlorinae, Salaccenses and Medusaeformes. Two species are illustrated here representing different sections.

Habenaria cruciata J.J.Sm.

The identity of the section to which this species belongs is not clear to me, the plant habit consists of a rosette of leaves at the base of the long terminal inflorescence and to some degree the flowers are similar Schlechter's Habenaria umbonata on which the dorsal sepal and the petals are simple and together form a hood, while the lateral sepals are deflexed and adpressed to the sides of the long spur.

The type specimen was collected in former Dutch New Guinea. The specimen illustrated here was collected from swampy ground in the Sepik region from Beowat and grown in a basket in the Bulolo Catholic Church collection. The flowers are green and pubescent.

Habenaria dryadum Schltr.

This species belongs to the section Salaccences which has around four closely related species. The plants in the section are usuually tall and with the terminal inflorescence some may be as tall as 70 cm. The spidery flowers are fairly large and numerous on the rhachis and the colours are usually light green to bluish green. The species in the section possess petals comprised of two long lobes. The lower one usually much narrower and more sinuous and similar to the long lateral lobe of the labellum. These features separate the section from the others where the petal is not divided or where the petals and the labellum lobes have numerous filaments.

The specimen illustrated here was collected at around 1,700 metres altitude in a pandanus forest in the Watut Valley near Bulolo, Morobe Province.

Phaius Lour.

Three sections are represented in New Guinea. These are Eu-Phaius, Persomeria and Limatodes. There are around six species found in Papua New Guinea. Two in each of the first section, three in the second and one in the third. The New Guinea representatives in the first two sections need to be examined further as one yellow flowered species currently lumped with P. tancarvilliae (Bl.) O. Ktze. may prove to be another species. The second in section 2. has yet to be identified and is close to P. pictus whiich is also found in Papua New Guinea

Phaius tancarvilleae (Bl.) O. Ktze.

The species is a representative of the section Eu-Phaius. It grows to a large plant up to 150 cm tall in optimum conditions. The leaves are around five or more to a pseudobulb, they are petiolate, large, broad, elliptic, fleshy and plicate; the thick, fleshy, pseudobulb can be up to 20 cm or more tall. The erect glabrous inflorescence has a thick peduncle. It arises from nodes near the base of the pseudobulb and is taller than the foliage. The rhachis bears few to many large flowers. The flowers initially present themselves in a porrect position but droop when pollinated. The back of the tepals is white and the face side is usually brown to light brown. The labellum is large and tubular with two keels in the throat. The lateral lobes are pink, brown and maroon and the mid lobe is usually white. These colours alter with age.

A very common species in New Guinea found in swampy parts of grasslands and on the border of secondary regrowth from 700 to 2,000 metres altitude

Phaius amboinensis Bl. var papuanus

This species belongs to the section Persomeria which is distinguished from the others by the long stems of the plants and the the production of a shorter inflorescence from stem nodes well above the ground

The flowers of the New Guinea variety of this species are not as large as the previous species. They have white tepals and the labellum is yellow. The appearance and colour of the flower reminds one of the flowers of Daffodils.

This specimen was collected from Oomsis Hill, at 300 metres altitude, in dense tropical lowland forest

Thrixspermum Lour.

A monopodial genus represented by about 10 species in New Guinea. All but one species are epiphytic. The plants may have long or short stems woth long or short, narrow or broad flat leaves. The flowers are short lived and produced one to two at a time.

There are two sections in the genus. section Thrixspermum in which the rhachis is flat and produces flowers and bracts in two rows. The second section Dendrocolla produces its flowers and bracts on a short rhachis with the flowers and bracts facing in all directions. Two examples of the first section are illustrated here. The second section has the common T. congestum as member. Common though it may be an illustration is not available and readers are referred to Dockrill'book on the Australian Indigeneus Orchids (Dockrill, 1969).

Thrixspermum amplexicaule (Bl.) Rchb. f.

The only terrestrial species, this is wide spread from New Guinea to SE Asia. The stems attain a length of up to 2 metres; it has a creeping scrambling habit. The leave are thick, fleshy and amplexicaule. The Inflorescence has a long peduncle and produces a pale mauve flower around 3.5 cm wide. The pouched labellum is shorter than the petals and it has a small yellow callus in side.

The specimen illustrated was collected from a swamp pond at Bulolol, Morobe Province, growing among the reeds and ferns. The species shows a preference for such situations where it has been collected. The species is known from localities near Lae and Garaina in the Morobe Province, Kunjingini in the Sepik and from Erave in the Southern Highlands. The species would be an interesting addition to a fishpond environment.

Thrixspermum warianum Schltr.

A short epiphtic plant up to 20 cm long, with long roots. The leaves are up to 10 cm long by 3 cm wide, they are oblong-ligulate, obtusely bilobed and ridged and fleshy and dark brownish green. The inflorescence has a short peduncle, the rhachis usually grows longer. The flowers are light yellow to cream; they are spider-like, similar to the common and wide spread T. platystachys but with shorter and stouter petals and sepals. The labellum is slightly shorter than the tepals, it has a distinct transverse red band as illustrated, and a red callus near the base inside.

This species has been collected in the Waria valley, at Erave in the Southern Highlands and

References
Dockrill, A.W. 1969. Australian Indigenous Orchids. Ssociiety for the Growing Australian Plants. 544-5.
Howcroft, N.H.S. 1992. The Onion Orchids of Papua New Guinea. New Guinea Field Note Extracts Part 8. In Orchid News. March. Orchid Society of PNG. 11-15.
---------- 1992. Jones, D.L. 1988. Natiive Orchids of Australia. Reed Australia p 400.
Lewis, B. and Cribb, P. 1989. Orchids of Vanuatu. Kew .153-4.
---------- 1991. Orchids of the SSolomon Islands and Bougainville. Kew 306-8.
O'Byrne, P. 1991. Two Members of Dendrobium Section Rhopalanthe and Aporum. In The Orchid News. June. Orchid Society of PNG. 11-15.
Omerod, P. 1992. A Note On The Large White Flowered 'Aporum' Of New Guinea. In The Orchid News. November/ December. Orchid Society of PNG. 23-24.
Schlechter, R. 1911-14. The Orchids of German New Guinea with Figure Atlas . A Translated version 1982. Australian Orchid Foundation.
Spence, P. 1992. Dendrobium convolutum Rediscovered. In Orchid Newsletter.
Vermeulen, J.J. 1991. Orchids of Borneo Vol2:263.