Genus of the Month: Robiquetia

August 2023 - by by Thomas Mirenda and Ron McHatton

Though there are some 70-plus species, very few have made it into cultivation, and many are the result of taxonomic lumping and redistribution of genera such as Malleola and Abdominea. The type species, Robiquetia ascendens, was described by Charles GaudichaudBeaupré in 1829. Because his generic circumscriptions were largely ignored by other botanists who followed him, most species described in the 19th century were placed in the broadly defined Saccolabium. Early in the 20th century, the work of J.J. Smith and Schlechter resulted in the recognition of the genus as distinct, and many species now included in the genus Robiquetia may have been previously placed in Cleisocentron, Aerides, Sarcanthus, Pomatocalpa, Gastrochilus and even Rhynchostylis, making for a very confusing array of synonyms and troublesome taxonomic webs. All of these sarcanthine genera are closely related and the phylogeny is not yet fully understood.

Widespread through much of Southeast Asia, from southern China, India, Indonesia, the Philippines, New Guinea and several of the Pacific Islands, the genus’s distribution through such diversity of habitats and geographic isolation on islands and mountain ranges accounts for much of its rampant speciation. Happily, most species are from lowland rainforests, keeping their culture far less complicated. Most species are stout, climbing epiphytes that eventually become pendent and branching over time as they mature. Their inflorescences bear rather small, but tightly clustered, usually succulent, almost berry-like flowers in pendent racemes that can be very attractive. Inflorescences produce new flowers at the tip of the inflorescence as spent flowers drop off, extending the flowering period to a month or more. Few of the species open widely and most have a curved, helmet-like dorsal sepal adding to the berry effect. One characteristic shared by all the species is the presence of a prominent, fleshy spur.

Robiquetias should be grown like Aerides; bright, but not full, light levels and even intermediate to warm temperatures (60–65 F [15.6–18.3 C] at night and 75–85 F [23.9–49.4 C] during the day) with frequent watering. Most species seem to prefer being grown in some form of potting medium (unlike vandas, which thrive in an empty basket). A mediumgrade fir bark–charcoal mixture in clay pots has worked well for some growers. Flower color in Robiquetia varies from pure white (Robiquetia compressa), to yellow variously marked with brown (Robiquetia spathulata and Robiquetia pantherina are examples) to deep reddish purple (both Robiquetia mooreana and Robiquetia cerina share this color form) to near-black (the Australian Robiquetia wassellii, for instance).

[1] This exceptionally well-grown cultivar of Robiquetia cerina received a 95 point Certificate of Cultural Excellence when exhibited at the Northeast Center monthly judging in Boylston, Massachusetts in September of 2015. The plant, Rbq. cerina ‘Marlow Orchids’, CCE/AOS, was grown by Jim Marlow and photographed by Teck Hia.

[2-4] The flowers of Robiquetia cerina have the widest range of color variation in the genus from yellow to shades of redorange to red-purple to bright purple. Robiquetia cerina was first described as Saccolabium cerinum in 1888. In 1915, Ames described Malleola merrillii moving it to Robiquetia in 1922 without recognizing its synonymy with the older Robique tia cerina name.

The most likely species you may encounter is Robiquetia cerina. It is endemic to the Philippines, but the first author has found it to be quite amenable to cultivation. A variable species with a several color forms, such as yellow, red and purple, this species (as is the case for most species of Robiquetia) thrives in most humid greenhouses under cattleya or phalaenopsis conditions, preferring bright shade, intermediate to warm temperatures and fairly high humidity. Plants are robust and the light green leaves have lightly serrate apices. The flowers of this species (Robiquetia merrillii is considered a synonym) are so tightly packed on the inflorescence that it is said one can actually squeeze the flower cluster without damaging the individual flowers. One drawback of this species is its tendency to produce roots only at the base of the plant and not intermittently along the stem. This makes it difficult, unlike many vandaceous species, to “top”; apical cuttings simply do not produce roots and the plants rarely produce lateral shoots. In mature plants, basal keikis are formed, leading to specimen plants.

Species such as Robiquetia mooreana (New Guinea) and Robiquetia ascendens (from the Moluccas) may look somewhat similar floristically but offer distinctly different plant habits and inflorescence lengths as they mature. Robiquetia mooreana produces large, showy clusters of deep red–purple flowers on some of the largest plants in the genus, with plants reaching upwards of 16 inches (40 cm) and leaves up to 8 inches (20 cm) long and 2 inches (5 cm) wide.

[5] Robiquetia cerina is endemic to the Philippine archipelago. A very similar species, Robiquetia mooreana is found from New Guinea westward to the Solomon Islands. Superficially similar, the flowers of Robiquetia mooreana open far more widely than those of Rbq. cerina and it is this feature that is perhaps most easily used to distinguish the two species.
[6] Robiquetia spathulata (pictured here) and Robiquetia pantherina is another pair of superficially similar species with widely disparate ranges; the former species found from the eastern Himalayas to Malesia and Hainan island in China while the latter species is endemic to the Philippines. The two are most easily distinguished in flower by the sharply defined white lines down the center of the sepals and petals in Rbq. spathulata. The brown markings of Rbq. pantherina are randomly distributed without those white lines.
[7] Robiquetia mooreana produces some of the longest, most showy flower clusters in the entire genus.

Some of the other species are quite different, such as Robiquetia compressa, from the Philippines, so named because its stem is often flattened to the branch on which it grows. Its distinct white flowers, produced on branched inflorescences, have contrasting bright orange-red lip side lobes. The flowers of this species often open more widely than the previously mentioned ones. This species produces the longest spurs in the genus. Robiquetia spathulata is one of the few that open widely and make for a very different kind of show. The species is found from northeastern India and Yunnan Province of China through Bhutan, Myanmar (Burma), Thailand and Indochina. Its flowers have a white background color heavily overlaid with brown markings. The species is most easily distinguished from Robiquetia pantherina from the Philippines in that the brown markings of Rbq. spathulata are distinctly interrupted to produce a white line down the center of the sepals and petals. The flowers of Rbq. pantherina lack these white lines.

Little is known of the pollinators of the genus, although the prominent spur, copious nectar and tightly clustered flowers held well away from the plant suggest either bird (especially for those species that produce stout inflorescences) or butterfly pollination.

[8] Robiquetia compressa from the Philippines is a very distinctive species. Its bright white flowers are produced on large, branched panicles and have perhaps the longest spurs in the genus. In addition, the plant stems are flattened and often grown appressed to the tree limb or mount on which the plant is attached.
[9] Most commonly a rich, shiny green, the flowers of Robiquetia wassellii from northern Queensland, Australia can be so intensely colored that, in some plants, the flowers appear to be black.

This genus was named for a French chemist and pharmacist, Dr. Pierre-Jean Robiquet, to whom we owe quite a debt. He was the discoverer of both caffeine and morphine and frankly, we could not wake up in the morning, or survive painful trips to the hospital, without his innovations. The genus honors him and his contributions to our pharmacopeia. Whether robiquetias stimulate you or put you to sleep, they are a fitting tribute to the man.

— Tom Mirenda has been working professionally with orchids for over three decades. He is currently an AOS trustee and is a past chair of the AOS Conservation Committee. He is an AOS accredited judge in the Hawaii Center (email: biophiliak@ Ron McHatton has been growing orchids for nearly 60 years and is currently the Society’s Chief Education and Science Officer. He is an accredited judge in the Florida North-Central Center (email

 August 2023
August 2023
The June 2023 issue contains articles from “PERFECTION” to “MALAXIS DRESSLERIANA" and more.

Also in this issue

  • Tom's Monthly Checklist by Thomas Mirenda
  • Collector's Item - Paphiopedilum concolor by Judith Rapacz-Hasler
  • Orchids Illustrated - Brownleea by Wesley Higgins and Peggy Alrich
  • Perfection - A Family Story; the development of white phalaenopsis by Robert Griesbach
  • Orchids of Bhutan - Chiloschista by Pem Zam and Stig DalströmMalaxis dressleriana sp. nov. by Isler F. Chinchilla, Adam P. Karremans, and Mario A. Blanco
  • Lindleyana - New Records of Lepanthes Sw. from Ecuador, Part 5: Two New Species and a New Record for Ecuador by Alfonso Doucette, Hugo Medina and José Portilla
  • Book Review - Demystifying Orchid Pollination: Stories of Sex, Lies and Obsession by Gab van Winkel