Seeds of South Australia
Eucalyptus youngiana (Myrtaceae)
Yarldarlba, Large-fruited Mallee
List of species for Eucalyptus
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Seed collecting:
January to December
Herbarium regions:
North Western, Nullarbor, Gairdner-Torrens, Eyre Peninsula
NRM regions:
Alinytjara Wilurara, South Australian Arid Lands
IBRA regions
Gawler Volcanics (GAW02)Gawler
 Rare   (IUCN: RA d(i,ii))
Kingoonya (GAW05) 
 Rare   (IUCN: RA d(i,ii))
Maralinga (GVD03)Great Victoria Desert
 Least Concern
Kintore (GVD04) 
 Rare   (IUCN: RA d(i))   [locally common]
Tallaringa (GVD05) 
 Near Threatened
Yellabinna (GVD06) 
 Rare   (IUCN: RA d(i,ii))
Carlisle (NUL01)Nullarbor
 Data Deficient   [no records]
Nullarbor Plain (NUL02) 
 Rare   (IUCN: RA d(i,ii))
Breakaways (STP01)Stony Plains
 Rare   (IUCN: RA d(i,ii))   [limited habitat]
Watarru (CER02)Central Ranges
 Rare   (IUCN: RA d(i))
RSCA map:
Regional Species Conservation Assessments per IBRA subregion. Please click the thumbnail map.
AVH map:
Australian distribution map (external link)
SA Census:
Census of South Australian plants (external link)     [genus Eucalyptus]
Name derivation:
Eucalyptus from the Greek 'eu' meaning well and 'calyptos' meaning covered, alluding to the cap or lid which covers the stamens in the bud. Youngiana named after Jess Young, an explorer who accompanied Ernest Giles during his fourth expedition, making some important botanical collections, including the 'type' specimen.
Distribution:
Found in the western part of South Australia, growing on deep red sand on dunes an in swales and on outcropping granite monoliths and rocky hillslopes. Also found in Western Australia.
Status:
Native. Uncommon in South Australia. Uncommon in Western Australia.
Plant description:
Multi-stemmed mallee to 10 m tall with rough, fibrous, dark grey-brown bark on lower stems and smooth, pinkish-grey to creamy bark above. Juvenile leaves ovate to broad-lanceolate, dull, blue-green. Adult leaves to 150 mm long and 40 mm wide, lanceolate to broad-lanceolate, dull, blue-green. Flowers axillary in groups of 3. Buds to 65 mm long and 40 mm wide, coarsely ribbed; bud-cap horn-shaped, equal to the base. Flowers pale yellow to red appearing in autumn to spring.
Fruit type:
Very large and woody fruit to 45 mm long and 70 mm wide, coarsely ribbed; disc broad, concave and ascending, valves 4-6 rim level or slightly above.
Seed type:
Brown irregular pyramid-shaped seed to 4.5 mm long and 2.5 mm wide.
Embryo type:
Folded.
Seed collecting:
Collect mature  fruits that are dark and hard (difficult to break with a finger nail), with the valves  unopen,any time of year.  
Seed cleaning:
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.
Seed viability:
From two collections, the seed viability was average to high, ranging from 65% to 100%.
Seed germination:
Seeds are non-dormant so viable seed should germinate readily.
Seeds stored:
LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
10200 (153 g)
10200 (152 g)
>5028-Oct-2004MOL 4648
Gairdner-Torrens
31-Mar-2006100%-18°C
BGA21000 (52.47 g)3019-May-2014DEM7737
North Western
24-Mar-201565%-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.
Germination table:
DateResultT0T50Pre-treatment | Germination medium | Incubator: Photoperiod / Thermoperiod
Aug-1480%7 d14 d
1% agar;
12/12;  /  20°C
Result: Maximum percentage of germination observed.
T0: Number of days before first germinant observed.
T50: Number of days to achieve 50% germination.
Pre-treatment: The initial treatment that the seeds received prior to placement on germination media.
Germination medium: The substrate that seeds were placed on for the duration of the germination experiment.
Incubator conditions:
Photoperiod: The duration of light exposure that the seeds were subject to during a 24 hour period.
Thermoperiod: The constant or diurnal temperatures that seeds were subject to during a 24 hour period.
Winter conditions: 15°C 20 h (3am→11pm); 5°C 4 h (11pm→3am) / 10 h light (8am→6pm); 14 h dark (6pm→8am)
Spring/Autumn conditions: 22°C 12 h (8am→8pm); 10°C 12 h (8pm→8am) / 12 h light (8am→8pm); 12 h dark (8pm→8am)
Summer conditions: 30°C 14 h (6am→8pm); 15°C 10 h (8pm→6am) / 14 h light (6am→8pm); 10 h dark (8pm→6am)