Prior names
Zygophyllum humillimum
Common names
Small-fruit Twinleaf
Etymology
Roepera (formally Zygophyllum which is from the Greek 'zygon' meaning pair and 'phyllon' meaning leaf; referring to the pair of leaflets making up each leaf) is named after Johannes August Christian Roeper (1801 -1885), a German botanist and physician. Humillima is the superlative of the Latin 'humilis' meaning very small; referring to its small fruit relative to other Roepera.
Distribution and status
Found in the north-eastern part of South Australia, growing on cracking clay and sandy loam with gypsum. Also found in Queensland and New South Wales. Native. Uncommon in South Australia. Rare in the other states.
Herbarium regions: North Western, Lake Eyre, Flinders Ranges
AVH map: SA distribution map (external link)
Plant description
Small prostrate annual herb 10 cm high. Leaves continuous with the petiole, leaflets oblong to obovate-cuneate, to 10 mm long, apex with a slight notched. Inflorescence on a very short stalk with small yellow flowers. Flowering between July and September. Fruits are tiny brown globular-campanulate capsule to 4 mm long, 4-angled, apex slightly dome-shaped with a minute membranous appendage forming a slight corner at upper part of each angle, one seed per segment. Seeds are shiny semi-flat brown, ovoid to 2.5 mm long and 1.5 mm wide. Seed embryo type is spatulate fully developed.
Seed collection and propagation
Collect seeds between September and November. 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. Place the capsules in a tray and leave to dry for 1 to 2 weeks, depending on how green the fruit is. 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 is usually high.
| Location | No. of seeds (weight grams) | Number of plants | Date collected | Collection number Collection location | Date stored | % Viability | Storage temperature |
|---|---|---|---|---|---|---|---|
| BGA MSB | 1,950 (1.92 g) 1,690 (1.66 g) | 20+ | 7-Oct-2010 | TST1051 Lake Eyre | 1-Jan-2012 | 100% | -18°C |
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.