24 September 2010

Eremophila psilocalyx – Scrophulariaceae (Myoporaceae)

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Eremophila psilocalyx - Scrophulariaceae (Myoporaceae)

In older references Eremophila psilocalyx was known as Eremophila pachyphylla. However, the word eremophila means desert-loving, which is perfect for these common inland plants (Australia wide excluding Tasmania), who thrive in hot dry situations and prefer the heavier loams rather than too sandy, but some are also found in such habitats. Eremophila psilocalyx is a common and widespread shrub of the mallee region to the NW, North and NE of Esperance, preferring a fine sand/clay over limestone. It grows into a very symmetrical shape to over 3 metres (10’) in height, which demands attention even when not in flower.

The botanical name of psilocalyx means ‘bare or smooth calyx,’ which is a distinguishing feature, another is the hairless outside of the flower, so if comparing with similar species, those features are definitive. The stems and leaves are slightly wart covered (glandular), but not as pronounced as related species, plus young plants are a little viscid (sticky).

The flowers (to 2 cm (3/4”) in length, vary in color from white to a deep lilac/purple and bloom prolifically, but even when they finish and fall to the ground, the colourful display persists in the form of the large and similarly coloured calyx. Like many plants in this dry region, flowering in usually timed to match the rainfall, which for Eremophila psilocalyx is from July to October, although August and September would be the most reliable. Birds do occasionally visit this plant, but pollination is more likely from insects.

Update: December 2010
The WA Herbarium is now using a different classification system, in which the Myoporaceae family has now been absorbed into the Scrophulariaceae family.