Cymbidiums erythraeum and flavum
by Joshua White
Cym. erythraeum is a cool-growing epiphytic and lithophytic species. At first glance, this diminutive species appears to be rather unimpressive when compared to its larger and more dramatic close relative, Cym. tracyanum. However, it is worth growing in its own right and has its own unique charm.
It is the smallest species of the Iridioides Complex – the group of species comprising Cym. iridioides, Cym. tracyanum, Cym. erythraeum and Cym. hookerianum. Like the other members of this group, it blooms once per bulb and (with the exception of hookerianum) suffers leaf-tip dieback if not provided with clean water. So far I have found Melbourne water to be acceptable for these species, although have received reports from Perth that tracyanum and iridioides suffer significant leaf-tip dieback with their water.
In my experience it is relatively easy to grow, requiring similar care to other species in the group.
Currently, Cym. erythraeum is classified into two different varieties:
Cym. erythraeum var. erythraeum, the original type species from India, and
Cym. erythraeum var. flavum, found in China (originally designated as Cym. flavum).
Both varieties share several traits in common:
Long, narrow foliage
Blooming once per bulb (this is also shared by all other members of the Iridioides Complex)
Scented (another trait common to the Iridioides Complex), though not as strongly as tracyanum
Alba forms
Cym. erythraeum var. erythraeum
The original type species was described by Lindley in 1859 from a collection made by J.D. Hooker in Sikkim, India. Unfortunately the name Cym. longifolium has been incorrectly used for it for many years, when in fact the original longifolium specimen has been demonstrated to be Cym. elegans.
The blooms of Cym. erythraeum var. erythraeum share some traits with iridioides, featuring stripes on the tepals and a tapered lip. However, that is where the similarity ends; the tepals are long and narrow and the lip is white with few spots.
This variety is easily distinguished from the Chinese flavum by the following:
The blooms tend to be rectangular in shape with less curvature of the ventral sepals.
The aforementioned shape of the lip (tapering like Cym. iridioides).
A weakly-arching to near-pendulous spike.
In my experience the flowering period is different between the two forms as well: in Melbourne, var. erythraeum flowers in April & May, the intraspecific hybrid around June and var. flavum in July & August.
Both colour forms of Cym. erythraeum var. erythraeum are in cultivation in Australia, with perhaps the most well-known alba clone being ’Lois’. Selfings of ’Lois’ were made available through nurseries such as Barrita Orchids and started to flower in 2020, as shown in the photos below. This is my favourite form of the species.
A closeup of a single bloom of Cym. erythraeum var. erythraeum f. album.
A selfing of ‘Lois’ on its first flowering with 8 flowers on the spike.
Cym. erythraeum var. flavum
This variety was first described by Z.J. Liu & S.C. Chen in 2002 as Cym. flavum. The name likely derived from the fact that the alba form was found first, followed by the more common regular form. It was merged into Cym. erythraeum as a variety in 2009 (although there is a strong argument for it to be kept separate as a distinct species; as of April 2021, the RHS has permitted the registration of the cross between the two varieties due to their distinct differences).
Cym. erythraeum var. flavum bears a strong resemblance to Cym. tracyanum – with the exception of the lip, this variety looks very much like a smaller version of that species (a 2019 study showed that one form of erythraeum was a sibling to tracyanum, but with more species now analysed it is clear that both erythraeum and flavum are not as close to tracyanum as initially thought). The lip itself is rounded, like tracyanum, but lacks the ruffled edge, strong spotting and hairy callus ridges of that species.
Several key features differentiate var. flavum from the Indian var. erythraeum:
The tepals are more falcate (the ventral sepals in particular curve forward).
The lip is wider and more rounded.
The spike is long and high arching, making it useful for improving spike length in hybrids.
It blooms off small plants (a valuable trait for breeding).
Probably the most well-known clone of this variety is ‘Paradise’ CBR-ACE-FCC/AOC, owned by Royale Orchids and, to the best of my knowledge, used for all of their crosses involving Cym. erythraeum.
Cym. flavum ‘Paradise’
A very small plant at the July 2019 COSV meeting demonstrating the long, high arching spike of flavum.
Comparison of the regular and alba forms of flavum. Photo courtesy of Andy Easton.
The intraspecific hybrid of flavum ‘Paradise’ X erythraeum ‘Lois’, now registered as Cym. Royale Green Mist. As you can see, the flowers are intermediate between the two varieties.
Use in Hybridisation
The late Kevin Hipkins of Royale Orchids used the species significantly, including crossing the two different varieties (‘Paradise’ X ‘Lois’); seedlings of which started to bloom in 2018 (see photo above). Both erythraeum and flavum have been used, although flavum has been far more popular. As of May 2023, the following primary hybrids were known to exist (where known, the variety used is listed):
Samurai Feel (changningense X)
Mountain Mist (dayanum X)
Teeny Weeny (flavum X devonianum)
Memoria Evelyn Cuming (flavum X eburneum)
Gammieanum (erythraeum X elegans, which also exists as a natural hybrid)
Memoria Neal Crosswhite (X erythrostylum)
Ba Trieu (X floribundum)
A version using flavum ‘Paradise’ is in circulation in Australia
Veronica Clowes (flavum X hookerianum)
Vingtaine de Samares (flavum X insigne)
David du Puy (X seidenfadenii)
Toni Benton (flavum X iridioidies)
Despite the original version being made with flavum, this has also been made with erythraeum. Should the two species ever be split, this latter version will require a new grex name.
Zen Beauty (kanran X)
(flavum X lowianum) – made by Royale Orchids
(erythraeum X lowianum) – made by the author
No Hope (flavum X mastersii)
Red China (sinense X flavum)
Ken Siew (flavum X tracyanum)
Many of the above crosses using flavum were Kevin’s work, although Kevin Butler at Ezi-Gro and EYOF have also used it for their hybrids. He also used the species in a number of his hybrid lines, with Arachnid (x Death Wish) probably being the most well-known. Arachnid has been remade at least three times that I am aware of:
Death Wish 'Dark Invader' X Cym. flavum 'Paradise' (released 2015)
Cym. flavum 'Paradise' X Death Wish 'Withering Glance' (released 2018)
Cym. flavum 'Paradise' X Death Wish 'Dreamtime' (released 2018)
Kevin Hill and Pierre Pujol in the US are also using flavum in their lines, including:
Grand Eyrie (flavum ‘Paradise’ X Grand Monarch ‘Exquisitum’)
Sandia Sparkle (Pywacket X flavum ‘Paradise’)
Sylvia Darr (Pinata Magic X flavum ‘Paradise’)
Cym. Ken Siew (flavum X tracyanum) at Cal-Orchid (2019).
Cym. No Hope (flavum X mastersii), shown at the June 2018 COSV meeting.
Cym. Arachnid (Death Wish 'Dark Invader' X Cym. flavum 'Paradise').
A different Cym. Arachnid (shown at the June 2019 COSV meeting).
References:
Cymbidium erythraeum. Flora of China. Available at: http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242316337 [Accessed 26th April 2020].
Du Puy, D. & Cribb, P., 2007. The Genus Cymbidium, Royal Botanic Gardens Kew.
Huanga, J.; Chena, G.; Lia, T.; Huanga, Z.; Raoa, W.; Chena, J. 2019. The complete chloroplast genome of Cymbidium erythraeum (Orchidaceae). Mitochondrial DNA Part B, Vol 4., No. 2, 2517-2518. https://doi.org/10.1080/23802359.2019.1638322
This article first appeared in Cymbidium Chatter Issue 3D (April 2020) and was last revised 12th May 2023.