Accepted name: Dendrochilum tenellum (Nees & Meyen) Ames, Philipp. J. Sci., C 2: 318 (1907)

Subgenus – Acoridium. Section – Acoridium.




Acoridium tenellum Nees & Meyen, Nov. Actorum Acad. Caes. Leop.-Carol. Nat. Cur. 19(Suppl. 1): 131 (1843)

Dendrochilum junceum Rchb.f., Otia Bot. Hamburg.: 54 (1878).

Acoridium sphacelatum Ames, Orchidaceae 1: 1 (1905).

Dendrochilum sphacelatum (Ames) Pfitzer in H.G.A.Engler (ed.), Pflanzenr., IV, 50 II B 7: 112 (1907).


Origin in the Wild




Elevation in the Wild


300 – 2,495 metres


Habitat in the Wild


Dendrochilum tenellum is mainly found in mossy cloud forest growing on living trees where it forms large clumps. This species can also been seen growing on solitary trees in open fields in bright light. This species has also been collected in upper rainforest, primary forest, on ridge tops and in scruby heaths.  Ames wrote that this species has been noted as growing on trees and rocks. This species has been collected throughout the Philippines and is the most commonly encountered Dendrochilum there.


This species has been recorded from Luzon; Benguet Province, Mount Santo Thomas, Baguio, Mount Tonglon and Nagulian; Bataan Province, Lamao Forest Reserve, Mount Mariveles and Mount Limay; Cagayan Province, Mount Cagua and Mount Balatongan; Camarines Sur on Mount Isarog; Ifugao, Mount Himi-o, Mount Pimmage, Mount Polis and at Sumigar; Ilcos Norte on Mount Burney; Kalinga-Apayao, Balbalan and Mount Sulu; Laguna on Mount Banahao and Mount Maquiling; Mountain Province on Mount Masapalid;  Nueva Ecija; Nueva Vizcaya; Pampanga on Mount Pinatubo; Pangasinan; Quezon on Mount Camatis; Rizal; Sorsogon on the Bulusan Volcano; Zambales on Mount Apoy.


On Mindoro it has been found on Mount Halcon and in within the Babuyan Islands.


In the Visayas it has been found on Leyte Island, Buenavista and Masaganap near Jaro, on Mount Mamban and Mount Suiro.


Mindanao; Camiguin Island on Mount Camiguin; Davao del Norte Province on Mount Kampalili.


Henrik Pedersen wrote that he observed this species growing on exposed solitary tree trunks and branches on Mount Santo Thomas. I have seen other in-situ photos where this species is growing in full sun light (Pedersen 1997).


The Plants Description


The pseudobulbs are terete and measure 1.2-8.1cm long and 2mm in diameter. The pseudobulbs are covered by 4-5 cataphylls while they are growing. The cataphylls disintegrate into persistent fibres as the pseudobulbs mature. The leaves are sessile, shaped terete to filiform are sedge like and have acute apices. The leaves measure 12.8-55.5cm long and 0.05-0.1cm wide.


The Inflorescence


The inflorescence emerges with the new growth. The peduncle is enclosed by the subtending leaf and appears to grow from its distal section, the overall length, including that within the leaf is 7.9-46cm long. The rachis measures 6cm long. The non-floriferous bracts appear imbricate. The flowers are spaced 4mm apart. The flowers open from the proximal or central part of the rachis.


The Flowers


The flowers are very small and measure 2-2.5mm across. Up to 30 flowers can grow on an inflorescence. The colour is cream to pale yellow, some flowers have been known to have an orange to red labellum. The dorsal sepal is shaped elliptic to oblong and has an obtuse to acute sometimes finely mucronate apex. The dorsal sepal measures 1.4-2.3mm long and 0.5-1.1mm wide. The dorsal sepal has an entire margin and is 1-3 veined. The lateral sepals are shaped broadly elliptic-oblong, ovate-lanceolate, oblong-lanceolate and have obtuse to acute, sometimes mucronate apices. The lateral sepals measure 1-2.5mm long and 0.6-1.2mm wide. The lateral sepals have entire margins and are 1-3 veined. The petals are shaped oblanceolate, rhomboid-spathulate and have rounded to obtuse or obscurely apiculate apices that are narrower basally. The petals measure 1.3-2.2mm long and 0.6-1.5mm wide. The petals have entire margins and 1-3 veined. The labellum is tiny, concave at its base and 3-lobed. The labellum measures 0.5-0.8mm long and 0.8-1.6mm wide. The labellum is 3-veined and has entire margins. The side lobes are erect, shaped ovate-falcate and have rounded to obtuse apices. The side lobes exceed the mid-lobe. The mid-lobe is shaped rounded-apiculate and appears triangular when the labellum is spread out; the apex is acute and recurved. There are three calli, two of which are lateral and one central. The column is tiny and measures 0.4-0.9mm long. The column has a projected rostellum. The anther cap is shaped broadly elliptic-orbicular from an upper view and rounded to roughly acuminate from its front.


Herbarium Specimens




Philippine National Herbarium (PNH)


Specimen – destroyed (Acoridium sphacelatum)


I could not locate the type of Acoridium tenellum







Specimen 1058 (photo) (Acoridium sphacelatum)

Specimen 57 (photo) (Acoridium sphacelatum)


New York Botanical garden (NY)


Specimen 39523 (photo) (Acoridium sphacelatum)



Other herbarium specimens


National Herbarium Netherlands (L)


Specimen L0322771

Specimen L0322772

Specimen L0322773

Specimen L0322774

Specimen L0322775

Specimen L0322776

Specimen L0322777

Specimen L0322778

Specimen L0322779

Specimen L0322780

Specimen L0322781

Specimen L0322782

Specimen L0322783

Specimen L0322784

Specimen L0322786

Specimen L0322787


Royal Botanic Gardens, Kew (K)


Specimen 61437.000

Specimen 60106.000

Specimen K000364831






Flowering Season


Flowering plants have been collected in the wild throughout the year except during August. In northern hemisphere cultivation plants can flower in winter and spring. The new growths generally appear from autumn.




This species is often seen in cultivation globally. I have seen plants in New Zealand, Australia, Europe and the USA.


Flowering triggers for my plants have been brighter light and lower night temperatures from the end of autumn until early winter. My experience suggests that this plant benefits from brighter light year round combined with cooler night temperatures and plenty of air movement. Water the plant from the bottom and don’t poor water over the plant, particularly if there are new growths.


Similar Species


Dendrochilum williamsii (Please refer to this page for the differences)

Dendrochilum graminifolium


Other Information


Oakes Ames described the synonym Dendrochilum sphacelatum in 1905, I have included Ames description above. When Ames described Dendrochilum sphacelatum he wrote that is closely allied to the more widespread Dendrochilum tenellum. In Orchidaceae Facsimile 6, Ames wrote that because of the absence of material between 1905 and 1918 he had considered the 2 species to be the same. Ames, however still kept the 2 species separate. Ames transferred Acoridium tenellum to Dendrochilum in 1907.


Henrik Pedersen wrote that there are no close relatives but is primary affinity is with Dendrochilum luzonense, Dendrochilum williamsii, Dendrochilum stenophyllum, Dendrochilum graminifolium, Dendrochilum perplexum and Dendrochilum louisianum.


Henrik Pedersen wrote that this is the only Dendrochilum with perfect terete leaves.


The epithet refers to the slender and delicate habit of the plant.




AMES, Oakes. 1905, Illustrations and studies of the Family Orchidaceae Facsimile 1, Ames Botanical Laboratory, North Easton, Massachusetts, Boston.


AMES, Oakes. 1907, Orchidaceae Halconenses: An Enumeration of the Orchids Collected on and Near Mount Halcon, Mindoro, Chiefly By E.D. Merrill, Bureau of Printing, Manila.


AMES, Oakes. 1920, Illustrations and studies of the Family Orchidaceae Facsimile 6 The Orchids of Mount Kinabalu British North Borneo, Ames Botanical Laboratory, North Easton, Massachusetts, Boston.


COOTES, Jim. The Orchids of the Philippines, 2001. Timber Press, USA


COOTES, Jim. BANKS, David. 1995, The genus Dendrochilum A guide to the species in cultivation, Orchids Australia, AOC


PEDERSEN, Henrik. 1997, The Genus Dendrochilum (Orchidaceae) in the Philippines – A Taxonomic Revision. Opera Botanica, Denmark


World Checklist of Selected Plant Families. 15 October 2008. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; accessed 15 October 2008.