Drosera Ordensis Information

Drosera Ordensis A. Lowrie

Nuytsia 9 (3): 363-367 (1994)

A tropical, fibrous-rooted perennial plant with a rosette of many leaves densely covered in white woolly hairs; rosettes commonly forming large compact clumps. Active growth occurs just before, during and a little after the wet season. In the dry season, the juvenile leaves at the center of the plant remain dormant, protected from the desert-like conditions by the dense woolly covering.

Leaf – lamina suborbicular, 3-4 mm long, 3.5—5 mm wide, with retentive glands around margins, and smaller glands within; lower surface woolly with white, dendritic hairs; petiole oblanceolate, 0.5—1 mm wide near the base, 2—4 mm wide near apex, narrowed to 0.8 to | mm wide at lamina, commonly 3.5—5 cm long at flowering, later enlarging, both surfaces and margins woolly with white, dendritic hairs
.

Inflorescences |—4, with many flowers in a crowded raceme, 20-45 cm long; scape
woolly with white, dendritic hairs; pedicels 24.5 mm long.

Sepals obovate, 3.8 mm long, 2 mm wide, woolly with white, dendritic hairs.

Petals various shades of pink to almost white, obovate, with a strong mid-vein, 7 mm long, 3.5 mm wide.

Stamens 5, 3.5 mm long; filaments white; anthers yellow; pollen yellowish-orange.

Styles -3, white, 2 mm long, 0.1 mm diam., each repeatedly branched from a little
above base; stigmas pink (in pink-petalled specimens), white (in white-petalled spec-
imens), ovoid, 0.7 mm long, 0.15 mm diam.

FLOWERING: December—April. Dormancy dry.

Habitat: Grows in the sand near sandstone rock outcrops, often among cane grass
(Sorghum species).

Location: W.A.—Kununurra, Pago; N.T.—Keep River National Park.

Mature plants of D. ordensis are about 8 cm in diameter. On a few occasions, I have found giant specimens up to 20 cm diameter near Kununurra.

The dense white woolly covering on D. ordensis protects the juvenile buds from
desiccation during dormancy. They also capture moisture, such as that from condensation.

I have observed D. lanata, a species with a similar hair covering to D. ordensis,
trapping early morning condensation. Each dendritic hair and lateral spur point captures a minute drop of water from the moisture-laden air. The drops combine by gravity to form a larger drop at the base of each hair, these in turn combining to form larger beads of water at various points along the leaf. When the water droplets are large enough, gravity prevails and they fall to the soil at the base of the plant.