Seeds of South Australia
Isotoma petraea (Campanulaceae)
Rock Isotome
List of species for Isotoma
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Seed collecting:
September to February
Herbarium regions:
North Western, Lake Eyre, Gairdner-Torrens, Flinders Ranges, Eastern, Eyre Peninsula, Northern Lofty, Murray
NRM regions:
Adelaide and Mount Lofty Ranges, Alinytjara Wilurara, Eyre Peninsula, South Australian Arid Lands, South Australian Murray-Darling Basin
IBRA regions
Broughton (FLB02)Flinders Lofty Block
 Rare   (IUCN: RA d(i))   [not grazed]
Olary Spur (FLB03) 
 Least Concern
Southern Flinders (FLB04) 
 Least Concern   [on rocky outcrops]
Northern Flinders (FLB05) 
 Least Concern
Central Flinders (FLB06) 
 Least Concern
Eyre Hills (EYB03)Eyre Yorke Block
 Least Concern
Talia (EYB04) 
 Rare   (IUCN: RA d(ii))
Eyre Mallee (EYB05) 
 Least Concern
Braemer (MDD07)Murray Darling Depression
 Least Concern
Myall Plains (GAW01)Gawler
 Least Concern
Gawler Volcanics (GAW02) 
 Least Concern
Gawler Lakes (GAW03) 
 Rare   (IUCN: RA d(ii))
Arcoona Plateau (GAW04) 
 Rare   (IUCN: RA d(ii))   [very specific habitat]
Kingoonya (GAW05) 
 Least Concern
Torrens (GAW06) 
 Rare   (IUCN: RA d(ii))
Kintore (GVD04)Great Victoria Desert
 Least Concern
Yellabinna (GVD06) 
 Rare   (IUCN: RA d(i,ii))   [very specific habitat]
Barrier Range (BHC01)Broken Hill Complex
 Least Concern
Bimbowrie (BHC05) 
 Least Concern
Breakaways (STP01)Stony Plains
 Near Threatened
Oodnadatta (STP02) 
 Near Threatened
Murnpeowie (STP03) 
 Data Deficient   [query ID, unlikely]
Peake-Dennison Inlier (STP04) 
 Least Concern
Macumba (STP05) 
 Near Threatened
Witjira (STP06) 
 Near Threatened
Sturt Stony Desert (CHC02)Channel Country
 Least Concern   [undercollected]
Lake Pure (CHC07) 
 Near Threatened   [limited habitat]
Mann-Musgrave Block (CER01)Central Ranges
 Least Concern
Watarru (CER02) 
 Least Concern
Everard Block (CER03) 
 Least Concern
IBRA regions
5 of 6 subregionsFlinders Lofty BlockLeast Concern
, Rare
3 of 5 subregionsEyre Yorke BlockLeast Concern
, Rare
Braemer (MDD07)Murray Darling DepressionLeast Concern
6 of 8 subregionsGawlerLeast Concern
, Rare
2 of 4 subregionsGreat Victoria DesertLeast Concern
, Rare
2 of 4 subregionsBroken Hill ComplexLeast Concern
6 of 7 subregionsStony PlainsLeast Concern
, Near Threatened
, Data Deficient
2 of 4 subregionsChannel CountryLeast Concern
, Near Threatened
3 of 3 subregionsCentral RangesLeast Concern
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 Isotoma]
Name derivation:
Isotoma from the Greek 'isos' meaning equal and 'tomos' meaning, a cutting; referring to the equally cut corolla lobes. Petraea from the Latin 'petraeus' meaning of rocky places; alluding to the species habitat on rocky outcrops.
Hillsides and usually associated with rock outcrops.
Found in the drier parts of South Australia, growing on hillsides associated with rock outcrops. Also found in Western Australia, Northern Territory, Queensland and New South Wales.
Plant description:
Perennial herbs with glabrous branches up to 40 cm long. Leaves with stalk on lower parts but usually stalk-less towards the apices of branches, oblanceolate to elliptic, to 75 mm long and 35 mm wide, acute, sharply lobed and with irregular teeth, glabrous. Flowers singularly in the axils of leaf-like bracts towards the ends of branches with white or tinged bluish purple flowers. Sepals shortly connate, the lobes linear-triangular, to 12 mm long, pointed, corolla with a slender tube to 20 mm long, pale-green, the lobes oblong-oblanceolate, to12 mm long, abruptly constricted into a point, white or more or less tinged a bluish purple, glabrous. Flowering between June and December.
Fruit type:
Papery brown cylindrical capsules, scarcely ridged, to 22 mm long.
Seed type:
Reddish to dark brown cylindrical seed to 0.8 mm long and 0.4 mm wide, with a net-like reticulated surface.
Embryo type:
Spatulate under-developed.
Seed collecting:
Collect mature capsules, those that are turning a pale straw colour and contain brown seeds.
Seed cleaning:
Place the capsules in a tray and leave to dry for one weeks. Then rub the capsules gently by hand to dislodge the seeds. Use a sieve to separate the unwanted material. Be careful as the seeds are very small. 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%.
Seeds stored:
LocationNo. of seeds
(weight grams)
of plants
Collection number
Collection location
% ViabilityStorage
26515 (1.75 g)
25000 (1.78 g)
15-1626-Oct-2004DJD 30
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.