18 
Nancy T. Burridge. 
The leaves appear terete owing to the folding together of the two upper or 
adaxial surfaces. In the field the leaf blade is not closed so that it appears 
v-shaped in cross section. In herbarium specimens the blades are closed so that 
they appear u-shaped in cross section. The blade may be glabrous, glaucous, 
or pubescent. It is pungent pointed in all western species. The ligule 
iis a row of short hairs across the whole of the top of the sheath. Since the 
blade is narrower than the sheath there is a ridge, left on either side of the 
base of the lamina, which may become auriculate and which usually bears hairs 
longer than those of the ligule. Sheaths are glabrous, resinous or pubescent. 
Panicles are erect with branches spreading at anthesis. 
Bentham refers to the glumes as keeled but most of the western material 
have glumes either rounded or very slightly keeled. One mistake commonly 
made in connection with this genus is that the leaf is described as convolute. 
As will be seen by the above description this is not the case. References 
to open and narrow panicles are of little use since at anthesis all western 
species, at least, spread their branches out at right angles to the main rhachis. 
The spreading is due to a small swelling which appears at the base of each 
branch. In practically all herbarium material the branches have returned 
to the erect position. 
The closest affinity is with Plectrachne Henr. This genus is distinguished 
from Triodia because of its awn like lobes to the lemmas. In view of the varia- 
tion already present within Triodia this seems an inadequate feature on which 
to base a generic distinction. 
Other affinities are with Astrebla and Danthonia. 
Key to the Western Australian Species. 
Lobes of lemmas with conspicuous nerves and as long or longer than 
the entire portion where the nerves are obscure. 
Lobes of the lemmas scarious. Leaf sheaths not 
resinous, more or less woolly pubescent 
Lateral lobes of the lemmas obtuse .... Basedoivii 
Lateral lobes of the lemmas acuminate .... lanigera 
Lobes of the lemmas rigid, erect or spreading. 
Leaf sheaths resinous .... .... .... .... pungens 
Lobes of lemma short (except in T. Wiseana ). The nerves visible, under 
a lens, in both the base and the lobes. 
Lower glume with three to seven nerves. Lowest lemma 5-8 mm. 
long. 
Lateral lobes of the lemmas acute. Nerves 
of the palea winged. 
Lobes of lemma nearly as long as entire 
portion. Sheath orifice with stiff 
glistening hairs 4-5 mm. long. 
Leaves not glaucous .... .... .... Wiseana 
Lobes of lemmas short. Sheath orifice 
with short woolly hairs. Leaves 
glaucous .... .... .... .... brizioides 
Lateral lobes of the lemmas obtuse. Nerves 
of palea not winged 
irritans 
