The winning photograph for March 2019, was Corunasylis ciliata (syn Genoplesium ciliatum). As with so many orchids, it has undergone a few name changes. Originally Prasophyllum, then Genoplesium and currently Corunastylis
Although Genoplesium was split into two with only one species remaining in Genoplesium and the others placed into Corunastylis, this split has not been accepted by the everyone. For example, eflora of SA and PlantNET use Genoplesium whilst VicFlora uses Corunastylis.
Whilst researching C. ciliatum I came across images of Prasophyllum spp. being misidentified as Corunastylis spp. and as it was originally described in Prasophyllum it seems appropriate to examine the similarities and differences between the two genera.
In South Australia (SA), the most obvious difference would appear to be size but across the rest of the country some Prasophyllum species potentially can be similar in size to the much smaller Corunastylis, although Corunastylis species are never as large as many of the Prasophyllum species.
Some of the shared features of the two genera are
- multi-flowered on a single stem
- single tubular leaf
- flowers non-resupinate, that is the labellum is above the column and the dorsal sepal is below (the only other non-resupinate flowered orchids in SA are Gastrodia, Caleana, including Paracaleana, and Cryptostylis subulata)
- Grow as scattered individuals
| Prasophyllum | Corunastylis | |
| Size | Tends to be a larger plant (up to 150cm), but can sometimes be as small as Corunastylis | Always a small plant (maximum no more than 90mm) |
| Leaf | Leaf sheaf opens well below the inflorescence (flower head) | Leaf sheaf opens at the base of the inflorescence. |
| Leaf | Often withered at flowering | Not withered at flowering |
| Labellum | Immobile | Mobile |
| Usually curved backwards (recurved) resulting in an upright appearance of the flower. | Not recurved resulting in a more drooping appearance of the flower | |
| Season | Mainly spring flowering | Mainly autumn flowering |
References:
Jones DL A Complete Guide to Native Orchids of Australia including the Island Territories 2006
Prasophyllum and Corunastylis descriptions from VicFlora, accessed 1 May 2029
https://vicflora.rbg.vic.gov.au/flora/taxon/bbf0eb5e-fc8d-426b-9cac-58c384474e17
https://vicflora.rbg.vic.gov.au/flora/taxon/91aa3829-ead8-407f-9db7-db2357ddb7e1
Bates R & Weber J Orchids of South Australia 1990
Jones DL, et al, Australian Orchid Genera CD-ROM 2008 CSIRO
Thank you to Greg Steenbeeke for reviewing the article.
NOSSA 