The Species Orchid Society of Western Australia (Inc)

Ron Heberle's Caladenias

CALADENIA IN WESTERN AUSTRALIA AND
NATURAL HYBRIDISATION
R. L. Heber1e

The genus Caladenia in Western Australia has been widely and lavishly distributed over about 34,000,000 hectares within a rough triangle bounded by Shark Bay in the north. Augusta in the southwest corner and Israelite Bay in the south-east. Within this vast area grow the 40 species and 10 varieties that have been named and described
The genus reflects a tremendous diversification and a high degree of specialization and flourishes over a wide variation of geographic, climatic and ever-changing habitats. Caladenia plants seem equally at home in the high rainfall areas in the south-west corner and in the drier north and east and in the arid inland goldfields up to 600km from the coast.
My personal interest in terrestrial orchids comes from many years of exhibition and display to the public, visiting the same colonies at the same time each year and being constantly confronted with problems of identification. It seems to me that many of the problem forms of Caladenia are more likely to be hybrids than un-named species.
Five years ago I decided to make a project of attempting to isolate these "presumed" hybrids and match them to parent combinations, to record relevant information to press and photograph the specimens in the hope that this work might assist in the future naming of new species. Although I had previously seen "presumed" hybrids as far north as the Murchison River, eastward to the east of Esperance and inland to Coolgardie, I decided to concentrate this work in the extreme south-west corner with the expectation that hybridization would be more abundant in the integrated colonies there than elsewhere. As I live in Albany I could visit these colonies throughout the flowering periods.
So far, the most productive colonies have been those that grow adjacent to rivers, streams, lakes and swamps - and so on, and around granite rocks where the insects are very active. I hope to study the specific fertilizing insects in the future and possibly other species isolating mechanisms which may have broken down to produce hybrid swarms.
The project was undertaken with the expectation that hybrid progeny would generally exhibit prominent structural features of one parent rather than the other and that possibly the pod-parent or the pollen-parent would be dominant, but this is not always the case. Apparent indications that the cross between pod-parent and pollen-parent (A x B) and the reverse (B x A) produce two distinct and different hybrids, may well be evident merely that one parent is more dominant than the other, or that some back-crossing has occurred, or that the hybrid has "selfed" and thrown to one parent or the other. These are distinct possibilities in hybrid "swarms'. However, in the cross between Calda.multiclavia and Calda.filamentosa var.filifera, (fig. 1) each flower has dominant structural features from each of the parents!
Other pointers noted are that uneven and irregular calli rows, wavy and angular lateral sepals can assist in identifying hybrids. I also note that if either of the parents is a fire-stimulated flowerer the hybrids will be likewise.
The presence of a number of un-named species together with the so-called "complexes" such as that of patersonii - huegelii -filamentosa and doutchiae (which contains numerous variations, races and possible hybrids) further complicates a complex issue. Nevertheless I have enjoyed some success as preliminary findings suggest that apart from the isolation of early and late flowering species, most Caladenias hybridize naturally. Some are capable of crossing with a number of others, this being demonstrated by Caladenia flava - latifolia - reptans - marginata -filamentosa - doutchiae -patersonii - huegelii - radiata - lobata and cairnsiana.
At this early stage I note that certain hybrids have established colonies in the areas east of Esperance, Jerramongup and Manjimup, these being the crosses between Ca1da. flava and Calda. latifolia and between Calda. patersonii and Calda. dilatata var. falcata (fig. 2). The project suggests that Calda. ericksoniae (fig. 3) and Calda. Triangularis, (fig. 4) are in fact hybrids.

This report is tentative and preliminary and is made in the hope that enthusiasts may be influenced to do similar work in other areas. A combined effort should eventually bring into clearer focus hybridization of Caladenia in Western Australia. Meanwhile the author invites constructive criticism of this paper. A beginning must be made - especially as the W.A. Government plans to release a further 3,000,000 hectares of virgin land for agricultural development during the next ten years.
The following table is offered as a basis;

Natural Hybridization in Caladenia in South Western Australia

Summary of Table

Interim and preliminary figures suggest that out of the 40 Caladenia species named at least 26 hybridize and out of the ten varieties seven do likewise. There remain at least 19 collections of possible hybrids where further research is required to determine parentage. The collections have been made from approximately 180 locations. The bulk of collections fall within the 200km radius from Albany as shown on the map.
The decision to re-publish Caladenia in Western Australia and Natural Hybridization HEBERLE R. L. (1992) is to give background information from the original research and introductory information supporting this. Whilst the original thrust of that paper is still relevant to this follow up paper, subsequent taxonomic treatment and revision will drastically alter names used in the "TABLE", drawings and photos.
CLEMENTS M. A. (1989) listed 5 new species, 7 reinstatements and 9 elevated from varieties to specific rank.
HOPPER S.D. and BROWN A. P. (1996) currently have in Manuscript proposals to increase the numbers of formerly described and published Caladenias from 46 to approximately 126 with a break down of Calda. filamentosa (32) Calda. huegelii (20) Calda. longicauda (25) with minor additions to other species. There are also proposals to formally name and describe 14 hybrids, (we wait their publication with more than passing interest). They propose to erect a new genus to cover all the "BLUE" Caladenias and include a white and yellow form under Cyanicula and similarly with the Calda. barba-ossa and its variants under Drakonorchis. Ca/da. menziesii will become Leptoceras and Calda. aphylla to Praecoxanthus.
The names of all of the above have been prematurely released and widely published in books, papers, journals and lectures, and are currently in common use, however until validated under the Convention of the International Code of Botanical Nomenclature they are illegitimate (refer to
GEORGE A. S. (1995) and HEBERLE R. L. (1995).
From the above it will be apparent to amend the TABLE etc. in HEBERLE R. L. (1992) will be futile until such time as HOPPER & BROWN'S manuscript is validated, however CLEMENTS M. A. (1989) will be used at the Conference lecture and the display of coloured prints in the Exhibition supporting these papers.
Since 1982 the field research has been ongoing with numerous new areas and a more thorough search in areas previously visited, also the research area has been marginally increased to a 300km arc from Albany. The list of presumed hybrids continues to grow. An impetus to the research has been the study of species variants and recording these on colour slides. This has given a fascinating insight and a field of conjecture where hybrids that appear to have the same parentage demonstrate a remarkable variation, as most registrants would know hybrid vigour often gives the best of both worlds. This adds a new dimension to the paragraph in the first paper on this subject, and suggests for every variation of form and colour from either parent can produce a distinctly different hybrid.
There is a school of thought that natural hybridization springs from a disturbed environment, such as road and railway reserves and degraded areas around towns and industrial sites, our research suggests otherwise. Referring to this section in the previous paper, the major factor to natural hybridization seems to be the abundance of different species integrating and the prevalence of non specific pollinators and the climatic seasonal conditions that encourage pollination activity namely warm, calm slightly overcast days. These factors trigger orchid pollination strategies such as fragrance and pheromones with glands and calli in addition to colour and mimicry.
The previous statement that most Caladenias hybridize appears to be confirmed as many not listed in the first paper have been proved to hybridize. Specificity of "one to one" pollination is seriously questioned here, this may occur with a minority of species, however, our research suggests that non-specific pollinators prevail.
Positive identification of presumed hybrids is still a "Grey" area, with most hybrid progeny showing a dominant influence from one parent. It is a rare occurrence to split down the middle. Identification could be improved when taxonomists apply the new technologies of enzymes, electrophoresis and DNA fingerprinting with further research on pollinating specificity. This seems a long way off as most professionals in our experience show little interest in natural hybridization
It is unfortunate that the name TABLE in the first paper could not be amended and subsequently research included at this stage for reasons previously stated.

REFERENCES
Bates R. (1985)
George A. 5. (1995)
Heberle R. L. (1982)

Heberle R. L. (1995)

Hoffman N. & Brown A (1992)
Hopper S.D. (1979)

HopperS. D. (1991)

Acknowledgements.
Check List of Australian Orchid Hybrids.
Letters to the Editor. The Orchadian Vol. 11 No.9 430.
Caladenia in Western Australia & Natural Hybridisation.
The Orchadian Vol. No 4.78-83.
Taxonomic Treatment of South Western Australia Appraisal.
The Orchadian Vol. No.10479-486.
Orchids of South Western Australia Second Edition
University of Western Australia Press.
Natural Hybridisation of Caladenia.
Bulletin of W.A. Native Orchid Study of Conservation Group.
Caladenia History & Taxonomic Concepts.
Proceedings from the 12th. Australian Orchid Conference
O.S.W.A. Perth 17-23.
Acknowledgements are due to the W. A. Herbarium and to Mr. A. S. George for the use of his checklist of the Orchidaceae of W.A. (Nuytsia Vol.2, No 2, 1971). My particular thanks go to Mr. Herb Foote for assistance with photographs and specimens, Messrs. C. Sumner and E. Chapman for their field work and specimens; my wife Pauline and daughter Milanna their support in field work. I am indebted to Steve Clemesha for advice by correspondence and to Cohn Woolcock for drawings (Fig. 1-5) done especially for this article.

Figure 1. Calda. multiclavia and Calda. filamentosa var. filifera. This
hybrid is rare even though both parents are plentiful. Colouring is a beautiful shade of pink diffused through orange to red - from both parents.

Figure 2. Calda. patersonii x Calda. dilatata var. falcata. A common and widely distributed hybrid - stabilized into colonies in some areas. var. falcata shows little variation over a wide range but Calda. patersonii is very viable: hence the hybrid varies considerably. Colour is whitish to cream (rarely pale green). Tepals follow the structure of Calda. patersonii. The dilated labellum fringe and purple tip favour the other parent. This hybrid occurs also in most eastern states.

Figure 3. Calda. eriksoniae (= Calda. filamentosa x Calda. doutchiae?) Named by Nicholls in 1950 (collected by Rica Erickson) this taxon is very variable but experienced amateurs consider it to be the result of multiple hybridization between the "complexes": Calda. doutchiae - filamentosa - cairnsiana - radialis. All these have striped labellums. The hybrids are widely distributed and plentiful - especially inland. They reproduce vegetatively as do most of the parents.