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Nuytsia Vol. 7, No. 2 (1990) 
absent; (3) peduncles 1 or 2 per axil and often inserted on very short racemes (axes 1-5 mm long); 
(4) basal peduncular bracts solitary and persistent or (in A. abrupta and sometimes in A. ascendens 
and A. helmsiana) absent; (5) flower-heads globular or almost so; (6) flowers 5-merous (4-merous 
in A. barattensis)', (7) calyx gamosepalous (although deeply dissected in A. ascendens, A. helmsiana 
and A. menzelii)', (8) legumes usually firmly chartaceous; (9) seeds longitudinal. 
The "A. wilhelmiana group" is not readily accommodated in either Bentham’s (1864) or 
Pedley’s (1978) classifications of Acacia. This is because for phyllodinous species with globular 
flower-heads, these systems rely on the number of nerves per phyllode to ascribe species to either 
section Phyllodineae or Plurinerves. In the "A. wilhelmiana group" this is a variable character with 
the number of nerves varying from two to more than seven per phyllode, i.e. 
2 nerves per phyllode; A. helmsiana 
4 nerves per phyllode: A. abrupta, A. ascendens, A. brachypoda 
3 to 7 nerves per phyllode: A. cowaniana 
5 or more nerves per phyllode: A. wilhelmiana 
5 or 7 nerves per phyllode: A. viscifolia 
6 nerves per phyllode: A. menzelii 
8 nerves per phyllode: A. barattensis 
This is but one of many examples that demonstrates the need to reassess the classification of 
Acacia subgenus Phyllodineae in order to produce a scheme which better reflects natural groupings 
of taxa. 
Key to species of "A. wilhelmiana group" 
1 . At least some phy llodes 5 - 1 0 cm long 
2. Flowers 4-merous; phyllodes compressed, 
obscurely 3-nerved per face (S.A.) A. barattensis 
2. Flowers 5-merous 
3. Peduncles glabrous; phyllodes terete, 4-nerved (W.A., N.T.) 
4. Gland at base of phyllode 0-2 mm above the pulvinus; sepals united; 
legumes 2.5-3 mm wide (W.A., N.T.) A. abrupta 
4. Gland absent from base of phyllode; sepals ± free; 
legumes 5 mm wide (W.A.) A. ascendens 
3. Peduncles puberulous; phyllodes ± compressed, >4-nerved in all (including 
marginal nerves) 
5. Peduncle indumentum not prominent, hairs white; 
some or all phyllodes >6.5 cm long, phyllodes longitudinally grooved on 
each face (S.A.) gracilifolia 
5. Peduncle indumentum prominent, hairs light golden; 
few phyllodes to 6.5 cm long, 
the remainder shorter (S.A.) A. wilhelmiana (Flinders Range variant) 
1. All phyllodes 1-5 cm long 
6. Phyllodes flat (although often somewhat thick) 
