06 October 2009

Sphaerolobium drummondii


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Sphaerolobium drummondii

Sphaerolobium drummondii is a widespread upright shrub to around 1/2 metre (1'6") in height and like other small slender plants in this genus, receive benefits from periodic bushfires that reduce larger smothering vegetation and promote seed germination. Around Esperance it can be found to the west and east of the town, commonly in low-lying areas adjacent near coastal swamps that have a moist sandy but non-calcareous soil. Recently I discovered a large colony growing in white sand over limestone, however this is somewhat misleading because the overlying sand was not alkaline as any calcareous material had probably been leached from it and was now part of the limestone substrate. These habitats with underlying limestone retain moisture and permit root penetration, making them very different from deep calcareous sands that dry rapidly and consequently have less flora diversity.

Flowering is recorded from July to November, however timing would depend on location and moisture supply, but the colorful orange to red and occasionally yellow flowers are quite eye-catching and when in the right place at the right time, are not easily overlooked. There are a number of Sphaerolobium species that are difficult to separate here, but the calyx tube length, color and markings, plus the shape of the yellow eye at the base of the standard petal are important diagnostic features.