Threatened Species Unit, North East Branch
New South Wales Department of Environment and Conservation, 2004
ISBN: 174122 135 8
2. Description and Taxonomy
Grevillea beadleana is a single-stemmed spreading shrub up to 2.5 m high and 2 m wide. It generally grows in gritty loam among granite outcrops in open scrub or woodland at the tops of gorges or undulating terrain, and also along creek-lines. These are areas with hot, dry summers and cold, wet or dry winters where there is an average rainfall of approximately 8001250 mm per annum (Olde & Marriott 1995). Flowers are produced in spring to late autumn with birds and the introduced honeybee being their most frequent visitors.
The leaves are spreading, 817 cm long, 511 cm wide (Makinson 1991), and pinnatisect with secondary or sometimes tertiary divisions with oblong to triangular ultimate lobes 211 cm wide. The upper surface of the leaves is sparsely haired and carries the midvein as a sunken groove. The lower surface is white and hairy, with the mid- and lateral veins prominent and the leaf margins slightly curved backwards (Olde & Marriott 1995). The leaves on the specimen collected near Walcha in 1887 differ moderately from the material collected from the Guy Fawkes River National Park (McGillivray 1993) and resemble the material collected recently from near Enmore (L. Copeland pers. comm.).
The burgundy flowers of Grevillea beadleana are borne on a 3550 mm flower stem (Figure 1). The short stalk of the flower is up to 20 mm. The flower stem bears 2090 flowers which open progressively from the base of the inflorescence upwards, with a fully-open inflorescence resembling a toothbrush. Burgundy pollen is presented on the far end of the pistil (pollen presenter). The mature buds and flowers produce nectar (Smith unpublished data). Accounts of the floral morphology of G. beadleana can be found in McGillivray (1986, 1993).
The fruit is about 910.5 mm long and 5 mm wide (Figure 1). It is ovoid, narrowing gradually at the end, dorsally concave and has a dense cover of intertwined hairs with conspicuous purple stripes and blotches over a green background. The fruit can contain two ellipsoidal seeds approximately 9 mm long and 4 mm wide, the outer face with tiny wrinkles, and the inner face channelled around a flat central portion (Olde & Marriott 1995). The seeds do not bear an obvious food appendage or dispersal mechanism. Fruits soon open, releasing the seeds to the ground.
There are several species closely related to Grevillea beadleana including G. caleyi, G. willisii ssp. willisii, G. acanthifolia ssp. acanthifolia and G. longifolia. These species also belong to the toothbrush inflorescence group of Grevillea. G. aspleniifolia is another species that could be confused with G. beadleana as it has similar elongated, broadly linear, entire or toothed leaves. G. willisii ssp. willisii is vegetatively the most similar to G. beadleana but the species should not be confused in the field as they occur in widely-separated locations (McGillivray 1993). G. beadleana can also be confused in the vegetative state with Lomatia silaifolia .
McGillivray (1986) published the name Grevillea beadleana in honour of Prof. Noel C. W. Beadle, the founding Professor of Botany at the University of New England. The holotype is lodged at the National Herbarium of NSW (McGillivray 1993).
Grevillea beadleana is a member of the ancient Gondwanan family Proteaceae, which has had a presence in Australia for at least 65 million years (White 1994). The Proteaceae contains about 80 genera (1500 species) of which 50 genera (900 species) are found in Australia (Harden 1991). Grevillea is mostly restricted to Australia but is also found in New Guinea, Sulawesi and New Caledonia (Morely & Toelken 1983). Between 250 to 338 species of Grevillea are recognised as endemic to Australia, with 5368 species in NSW (Morely & Toelken 1983; Makinson 1991; Olde & Marriott 1995). G. beadleana is a member of the toothbrush inflorescence group of Grevillea. Several species within this group are threatened with extinction.
Figure 1. Inflorescence (x1.25), inner surface of tepals showing the anthers (x 5), flower and fruit (x 3.75) of Grevillea beadleana.