Seeds of South Australia
Zygophyllum rowelliae (Zygophyllaceae)
Rowell Twinleaf
List of species for Zygophyllum
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Seed collecting:
June to December
Herbarium regions:
North Western, Lake Eyre
NRM regions:
Alinytjara Wilurara, South Australian Arid Lands
IBRA regions
Tallaringa (GVD05)Great Victoria Desert
 Rare   (IUCN: RA d(i,ii))
Breakaways (STP01)Stony Plains
 Least Concern   [stronghold]
Oodnadatta (STP02) 
 Least Concern   [stronghold]
Witjira (STP06) 
 Rare   (IUCN: RA d(i,ii))
Baltana (STP07) 
 Rare   (IUCN: RA d(i,ii))
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 Zygophyllum]
Name derivation:
Zygophyllum from the Greek 'zygon' meaning pair and 'phyllon' meaning leaf; referring to the pair of leaflets making up each leaf. Rowelliae named after Alison Rowell, who assisted Hansjoerg Eichler with his work on Zygophyllum and many of the notes within the Eichler manuscripts were made by her.
Distribution:
Found in the central northern part of South Australia, growing in breakaways often in gravelly soils. Also found in the Northern Territory and Queensland.
Status:
Native. Uncommon in South Australia. Uncommon in the other states.
Plant description:
Erect initially the becoming decumbent and spreading, annual herb to 25 cm high, glabrous. Leaves succulent, ovoid Y-shaped, to 25 mm long and 14 mm wide, articulated from the stem. Inflorescence paired at each node with yellow flowers. This species is closely related to Zygophyllum iodocarpum and is distinguished from it by the somewhat larger flowers and the longer style with undivided stigma, visible in both flowers and fruits. Flowering between April and October, probably dependent on rain.
Fruit type:
Pale brown, elliptical capsule to 5 mm long, with 5-angles and 5-cells, rounded at apex, with 1-2 seeds per cell.
Seed type:
Black tear-drop seed to 2.5 mm long and 1.7 mm wide, with a slightly wrinkled surface.
Embryo type:
Spatulate fully developed.
Seed collecting:
Collect semi-dried and dried capsules by running your hands through the stems of the plant. Mature fruits will come off easily and will have a hard and dark seed inside each segment.
Seed cleaning:
Place the capsules in a tray and leave to dry for 1 to 2 weeks, depending on the greenness of the fruit. Then rub the dried capsules to dislodge the seeds. Use a sieve to remove the unwanted material. 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 one collection, the seed viability was high, at 100%.
Germination table:
DateResultT0T50Pre-treatment | Germination medium | Incubator: Photoperiod / Thermoperiod
Jul-1770%77 30% hydrogen peroxide for 10 min, water rinse, seed coat nicked with scalpel;
1% agar;
Incubated under winter conditions
Jul-1753%735 seed coat nicked with scalpel;
1% agar;
Incubated under winter conditions
Jul-1737%7NA 30% hydrogen peroxide for 10 min, water rinse;
1% agar;
Incubated under winter conditions
Jul-170%NANA leached in water 24 h;
1% agar;
Incubated under winter conditions
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)