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Telopea Vol, 6(4): 1996 
36. Metaxylem vessels; small (0); large (1). 
Metaxylem vessels are coded as small if they are less than 1/5 of the diameter of the 
vascular bundles. Variation in the relative size of the metaxylem vessels is continuous: this 
particular interval was chosen to maximise the informativeness of the character. 
37. Bulliform cells: absent (Fig. 5: A, D, K) (0); flanking midvein (Fig. 5: G) (1); ubiquitous 
(2)fadditive]. 
38. Abaxial epidermal thickening: absent (Fig. 5: I, L) (0); slight (1); extreme (Fig. 5: C) 
(2)[additivel. 
39. Sclerenchyma cap; small (0); large (1). 
A sclerenchyma cap appears to be consistently present in all danthonioid species. However, 
the degree of development of the cap varies: large caps are generally wider than the costal 
regions and, when well developed, are visible on the leaf margin as a narrow hyaline 
strip. This character is not visible where a continuous subepidermal sclerenchyma layer is 
present, but tliis is very rare in the Rytidospenna group. 
40. Number of primary vascular bundles (from margin to and including midvein); 1-3 (0); 
4-6 (1). 
This counts as the midvein and the number of primary vascular bundles in half the leaf. 
It is partially a measure of the width of the leaf. 
41. Macrohairs: absent (0); present (Fig. 5: H) (1). 
42. Abaxial silica; costal similar to intercostal silica (Fig. 5: C) (0); costal different from 
intercostal silica (1). 
43. Abaxial costal silica: saddle shaped (Fig. 5: I) (0); cork silica pairs (Fig. 5: C) (1). 
44. Intercostal silica bodies: rounded (0); elongated/kidney shaped (1). 
45. Abaxial microhair apical cell (a) to basal cell (b) length ratio: a/b>2 (0); 
1 < a/b < 2 (Fig. 5:1, L) (1); a/b < 1 (2)[addi«ve]. 
46. Abaxial stomata: absent (0); present (Fig. 5:1) (1). 
47. Abaxial prickles: absent (0); present (Fig. 5: H, I, K) (1). 
48. Adaxial papillae: absent (0); present (1). 
Adaxial papillae (Fig. 5: B, E) are commonly present and variable in shape and size in 
Chionochloa (Linder in prep). However, it is only sporadically present in Rytidospenna, 
and not variable in shape. Papillae also occur sporadically in several other genera of the 
danthonioid grasses. 
49. Chromosome number: diploid (0); tetraploid (1); hexaploid (2)[additive]. 
Tliis is based on the chromosome counts of Brock and Brown (1961), Bowden and Senn 
(1962), Gould (1958), Calder (1937) and Spies et al. (1992). All numbers are based on .r = 6. 
Taxa were scored as diploid if the chromosome numbers are in multiples of 12, tetraploid if 
in multiples of 24, and hexaploid if in multiples of 36. This coding system was employed to 
detect different 'basal' numbers for different genera of danthonioid grasses. Unfortunately, 
several critical genera (e.g. Plinthanthesis) are still unknown cytologically. Tlie count of n = 10 
for Rytidospenna oreoboloides (Borgman 1964) was ignored, as it has not been corroborated. 
Fig. 5. (right) Leaf anatomy of four species, displaying tlie major variation in the study group. A, B, 
D, E, G, H, J, K: transverse sections; C, F, I and K: adaxial epidermis. Sclerenchyma indicated by 
black shading. A-C; Rytidospenna montis-wilhelmii (Mclean & Wade 7285), note the silica bodies are 
all round, with no differentiation between the costal and intercostal zones. D-F: R. pauciflora (Linder 
5688), note small metaxylem vessels. G-I: Notodaiithonia pilosa (Linder 5571), note the macrohairs, 
unfurrowed leaves, numerous stomata. J-L: Ptinthanthesis rodwayi (Linder 5623), note the islands of 
colourless cells between the vascular bundles, and the rounded ridges on the leaves. Scale bar = 0.1 
mm, except for G and J, where it is 1 mm. 
