Plants of
South Australia
Eucalyptus cladocalyx ssp. crassa
Myrtaceae
Kangaroo Island Sugar Gum
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Etymology

Eucalyptus from the Greek 'eu' meaning well and 'calyptos' meaning covered; alluding to the cap or lid which covers the stamens in the bud. Cladocalyx from the Greek 'clados' meaning branch and 'calyx'; alluding to the flowers that occurs on older branchlets below the leafy part of the crown. Crassa from the Latin 'crassus' meaning thick or stout; referring to its coarse fruits compared to the other subspecies.

Distribution and status

Endemic to South Australia and restricted to Kangaroo Island, growing on undulating or hilly terrain, in gullies and on slopes forming a woodland or open forest. Native. Uncommon in South Australia.
Herbarium region: Kangaroo Island
NRM region: Kangaroo Island
AVH map: SA distribution map (external link)

Plant description

Single stemmed tree to 18 m tall, crown terminal and oftern layered, with smooth bark throughout, orange-yellow to tan, grey and cream. Adult leaves to 100 mm long and 35 mm wide, lanceolate to broad-lanceolate, glossy, dark green above and paler below. Flowers axillary in umbels of 7-11 flowers on leafless part of the branchlets. Buds to 13 mm long and 6 mm wide, cylindrical to urn-shaped, bud-cap hemisperical and rounded and much shorther than the base. Flowers cream appearing in summer. This subspecies is distinguished from the other two subspecies by its distribution and combination of tall, wide-branching habit, relatively long and broad adult leaves and relatively large fruits. Fruits are woody, barrel to urn-shaped fruit to 16 mm long and 11 mm wide, smooth or ribbed, disc descending, valves 3 or 4 deeply enclosed below the rim. Seeds are grey-brown ovoid seed. Seed embryo type is folded.

Seed collection and propagation

Collect seeds between January and December. Collect mature fruits that are dark and hard (difficult to break with a finger nail), with the valves un-open any time of year. Leave the fruits in a breathable container in a dry room for one to two weeks. This allows the valves on the fruit to open and release the seeds. Separate the seeds by placing all the materials into a bucket and shaking it to dislodge the seeds. Pass the material through a sieve to separate the unwanted material. The finer material will contain both seeds (soft) and frass (hard) usually distinguishable from each other but can be very similar in shape and colour. With finer sieves, the seeds can be separated from the frass but this is not essential for storage or propagation. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place. From one collection, the seed viability was high, at 100%. Seeds are non-dormant, viable seed should germinate readily.

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
3,550 (4.69 g)
3,550 (4.69 g)
1825-Jan-2007DJD755
Kangaroo Island
1-Aug-2007100%-18°C
Location: BGA — the seeds are stored at the Adelaide Botanic Gardens, MSB — the seeds are stored at the Millennium Seed Bank, Kew, England.
Number of plants: This is the number of plants from which the seeds were collected.
Collection location: The Herbarium of South Australia's region name.
% Viability: Percentage of filled healthy seeds determined by a cut test or x-ray.