Cyat-marc

Cyathea X marcescens - Skirted Treefern (Subg. CYATHEA, sect. Cyathea)

IDENTIFYING FEATURES:
* fairly rare and variable treefern (occasionally encountered with forked fronds or pinnae, or rarely with branched trunks) ... natural hybrid between C. australis & C. cunninghamii ... only found in deep moist mountain gullies in Victoria (with one record just over the border in New South Wales) where C. cunninghamii is found ... larger crown of fronds than C. cunninghamii ... black trunk, between C. australis & C. cunninghamii in size ... black stipe bases similar to C. cunninghamii ... old dead fronds usually retained throughout entire trunk as a 'skirt' (although occasionally C. cunninghamii will also have a skirt in very sheltered locations)
* indusium saucer-shaped, not quite as well developed as in C. cunninghamii

CYATHEA MARCESCENS PROPAGATED FROM SPORE?
(part of an article I had published in the newsletter of the Fern Society of Victoria in March '84)

     It is generally accepted that Cyathea marcescens (the Skirted Treefern) is a hybrid between the Rough Treefern
(C. australis) and the Slender Treefern (C. cunninghamii). As with many hybrids, it seems that the Skirted Treefern is sterile; all of my own attempts to collect and grow spore have been without success.

     Several years ago I was able to collect spore of C. cunninghamii and decided this was a perfect opportunity to attempt to cross this with C. australis. Many of the methods outlined in text books for crossing ferns sound rather technical and tedious, and so I opted for simply sowing both spore together and allowing nature to take its course.

     However, it seemed to me that sowing equal quantities of each parent would not encourage hybridization. If there are plenty of each parent present, then there seems to be a greater opportunity for each prothallus to be fertilized by the same species, and less chance of cross fertilization. However, if there are only a very few of one species present, there seems (to my brand of logic anyway) to be a greater chance of these few being fertilized by the other species present in large numbers.

     Armed with this conviction, I sowed a normal pot of C. cunninghamii and then sowed over this the smallest possible amount of C. australis spore. From this mixed sowing, as well as large numbers of C. cunninghamii and a few C. australis, there were a handful of plants that were not clearly distinguishable as either C. australis or
C. cunninghamii. They started off looking very like C. cunninghamii, but as they grew, the fronds seemed to become more like C. australis. However the crowns seem to retain the appearance of C. cunninghamii, with pale scales and dark stipes.

     Although botanically there is no definite evidence as yet that these are in fact hybrids, in my own mind I am convinced that some plants from this mixed sowing are neither C. australis nor C. cunninghamii, and I am certain these will prove eventually to be C. marcescens.

     Being a hybrid, C. marcescens has a very limited natural distribution, and is virtually not available commercially. So, I hope I can encourage many members to do something towards conservation of this rare treefern and attempt to grow some from spore.