Cycas couttsiana

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Contents

Common Names:

Cycas sp. 'Glen Idle Blue'

Notes:

(The following notes were written just after the discovery of C. couttsiana, and before its official description.)

With the blue foliage colouration having been mentioned by J.R. Maconochie speaking of Northern Territory Cycas species, it can well be imagined the excitement that followed reports of a blue-leaved Cycas from Queensland other than the elusive east coast Cycas cairnsiana.

It was noticed on a property directly north of Hughenden, central Queensland, near the Chudleigh Station. Mrs. Pat Coutts' property, 'Glen Idle' was used for the temporary name for the new Cycas. Preliminary investigation by collectors and taxonomists indicates that this is a new species. There are profound similarities between it and another 'blue' to be found about 150km directly north on Mt. Surprise and first brought to notice by Mrs. Irene Champion of Mackay, Queensland. This raises the question; Is this a northern colony of the other?. The terrain question would seem to deny this as Mt. Surprise is gemstone and granite country, whilst much of 'Glen Idle' is on deep red basaltic soil.

On examining two mature specimens in cultivation, it was found that at least two of the 'blue' Cycas have the tendency to lose the blue sheen if replanted in different soils and colour change is apparently seasonal at least in a coastal environment, as new fronds resume the glaucous sheen. However it is obvious that the seasonal change does not occur if plants are in their natural habitat.

'Glen Idle Blue' occurs inland of the Great Dividing Range and as it only grows on private property, very little information has been available to Australian investigators. However, I have reports from a reliable source that one giant specimen growing on the deep soil area has a measured height of 11.60m. The caudex was a single trunk having the visual appearance of the coastal Cycas media and the base at ground level had many age cracks between the old leaf bases. One can only guess the real antiquity of this specimen. The report goes further to state that several other plants measured in the vicinity of 6.0m tall. This must be taken to be exceptional as the average height seems to be about 3.0m. Sporophylls, ovules, new fronds and rachis shape all have profound similarities to the species found on Mt. Surprise gemfields. The deep soil area of 'Glen Idle' is an ironbark country and reports mention an outstanding eucalypt with a very rough yellow bark being everywhere, There are two possible species, but the most likely is Eucalyptus similis (Inland yellow jacket), a dominant species on the deep soil country, having a rough yellow bark to the trunk. The other is Eucalyptus peltata (Rusty jacket) which does grow in the area but generally a little farther north. The latter also has a rough yellow bark.

After close examination of two mature fronds, it is convincing to assume the affinity of the east coastal 'Blues' and other Cycas to the west. The as yet undescribed plants of Chudleigh Station, Mr. Surprise and the species directly north of them, Cycas cairnsiana, show many similarities despite the obvious height differences with the 'Glen Idle'. This could possibly be explained by environmental and geological changes in the habitat of each form.

Data Notes:

The mature rachis is 1.70m in length, and if flattened, 36.0cm wide, at the widest part. 78 pairs of pinnae to the rachis, pinnae being 18.0cm long and 5.0mm wide. spines on the rachis, 20 to 25 pairs, situated between the lower pinnae and the base of the rachis. The central nerve or vein of each pinnae is sunken above but prominent on the reverse side. Pinnae are stiff and revolute at the margins. One factor stands out to mark similarities and that is the way all of the mentioned forms have a distinct V-shape where the pinnae meet the rach is. A rusty-brown tomentum covers each side of the rachis, the frond itself glaucous blue.


Contributed by:

L. P. Butt (Text - from Palms & Cycads No. 27, Apr-Jun 1990).

External Links:

Cycad Pages, IUCN, JSTOR, Trebrown

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