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A key to yellow Thai Dendrobium orchids

March 20, 2011

At times you get an orchid as a present, and quite often the giver can not remember its name or never even asked for it. Previously I published a simple key to the terrestrial Thai orchid genera, and a simple key to Thai white and yellow Dendrobium species.

Since this is the time when about eight different yellow Thai Dendrobium bloom, and since most orchid books arrange the orchids alphabetically after their scientific names and therefore scatter similar species, I had a need for a key to make a quick identification.

1. Yellow lip pointed or with brown or black blotches……….such keys are under preparation!

1. Yellow lip roundish and uniformly yellow or with a deeper yellow or orange blotch………2

2. Side petals deeply ciliated………………………………..D. harveyanum.

2. Side petals smooth ………………………………………………………………..3.

3. Lip edge distinctly fringed……………………………………………………….4.

3. Lip edge smooth or almost smooth…………………………………………..6.

4. More than 10 flowers from each pseudobulb…….D. chrysotoxum.

4. Less than 10 flowers from each pseudobulb…………………………………5.

5. Flowers 3-6 per pseudobulb………….…………………D. chryseum.

5. Flowers 1-3 per pseudobulb………………………………D. jenkinsii.

6. Pseudobulbs 30-50 cm long………………………….D. dixanthum.

6. Pseudobulbs less than 30 cm……………………………………………7.

7. Pseudobulbs 15-25 cm………………………………D. sukhakulii.

7. Pseudobulbs less than 15 cm……………………………………………..8.

8. Flowers 12 or more per compact pseudobulb………….D. lindleyi

8. Flowers 2-5 per elongated pseudobulb……………….D. capillipes.


Dendrobium lindleyi is now in blossom at Dokmai Garden in Chiang Mai (Thailand). This specimen was labeled as D. aggregatum by the vendor, but that name is obsolete and may refer to either D. lindleyi or D. jenkinsii. Following the key above we quickly realize this is D. lindleyi. It has one leathery leaf on each compact pseudobulb (up to 7 cm long), and the leaves are present during blossom.

A close-up picture of D. lindleyi.

Dendrobium lindleyi (left) and D. jenkinsii (right) used to be fused into D. aggregatum. D. lindleyi has larger flowers (lip 3.5 cm broad vs 2.3 cm), larger pseudobulbs (7 cm vs 4 cm), longer leaves (9 cm vs 4.5 cm) and more flowers per inflorescence (more than 12 vs up to 3). The lip of D. jenkinsii has a deeper cleft (3 mm) than D. lindleyi (0-1 mm) and the margin is actually slightly fringed.

Dendrobium lindleyi (left) and D. jenkinsii (right) from behind.


Dendrobium chrysotoxum has a clearly fringed lip with brown hairs in the throat. The flower is more sturdy than the fragile D. lindleyi and D. jenkinsii. At Dokmai Garden it flowers one month later, at the end of April.


Dendrobium harveyanum has deeply ciliated side petals.

Comments to improve the key are most welcome: info@dokmaigarden.co.th

Did you know that Dokmai Garden has created an Orchid Ark?

Text & Photo: Eric Danell

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