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Telopea Vol. 6(4): 1996 
layers of palisade cells, and an inner parenchymatous region with vascular bundles. 
Both have a somewhat lignified hypodermal layer, clearly a xeromorphic feature 
(Fahn 1954). However, they differ from each other in several significant respects. In 
Kingia australis the vascular bundles are in a single row (all similarly oriented) with 
thick-walled fibres present in an arc at the phloem poles and interspersed in the 
phloem, also with a larger region of thinner-waUed fibrous cells present within the 
outer bundle sheaths (but never extending to the epidermis). In Xanthorrhoea australis 
(Fig. 2f) the vascular bundles are in 2-4 rows, oriented in opposite directions 
(i.e. leaf isobilateral, in contrast to all the other genera in question), and in the outer 
chlorenchymatous region there are sclerenchymatous girders formed from mesophyll 
tissue (rather than bundle sheath) linking the epidermis with the central 
parenchymatous region (Fig. 3f). Not all species of Xanthorrhoea have quadrangular 
leaves: some are U- or V-shaped in cross section (David Bedford, pers. comm.). 
In all the other genera, leaves are usually more or less U- or V-shaped in cross 
section (sometimes somewhat flattened in strap-like leaves), with vascular bundles 
in a single row (all similarly oriented). Baxteria (Fig. 3b) resembles Kingia in having 
both phloem fibres and a larger region of thinner-walled fibrous cells present within 
the outer bundle sheaths, but differs in having sclerenchymatous girders extending 
from the outer bundle sheath cells to the epidermis, i.e. formed from mesophyll 
tissue, as they are distinct from outer bundles sheath cells. This differs from the 
condition in Xanthorrhoea, where the girders do not extend from the bundles. Baxteria 
and Kingia also often have two peripheral phloem strands at vascular bundles, as in 
Dasypogon and Calectasia. 
Dasypogon (Fig. 2e, 3e) differs from all the other genera in having chlorenchyma 
present only on the abaxial side of the leaf and with a broad adaxial parenchymatous 
region containing the vascular bundles, which often have two peripheral strands of 
phloem. Calectasia (Fig. 2b) has a reduced leaf with only three vascular bundles, each 
with at least two peripheral strands of phloem. It resembles Dasypogon in lacking 
girders and having a thick, sclerenchymatous inner bundle sheath completely 
encircling the xylem and phloem regions of the vascular bundles. 
Xerolirion (Fig. 4a-c) also has a reduced leaf, with about three vascular bundles, but 
differs from Calectasia in that it has sclerenchyma girders (formed from the inner 
bundle sheath, as in the Loniandra-group), which extend along the abaxial epidermis, 
sometimes becoming isolated in small groups, as in Romnalda. 
Acanthocarpus (Fig. 2g) and Chamaexeros (Fig. 3d) resemble each other in having 
sclerenchyma girders of inner bundle sheath cells and enlarged parenchymatous 
outer bundle sheath cells, both characters also shared with Lomandra (Fig. 2c) and 
Romnalda. Romnalda grallata (Fig. 4d,e) and R. papuana both also have small isolated 
subepidermal abaxial and adaxial groups of fibres in the mesophyll, although these 
were not recorded by Staff (in Stevens 1978) for R. papuana, and may be variable. 
Silica and calcium oxalate 
Calcium oxalate raphides (bundles of fine needle-like crystals) are present in leaf 
mesophyll of Acanthocarpus, Chamaexeros, Romnalda, Xerolirion (and rarely Lomandra), 
often in enlarged idioblasts. In Calectasia and Dasypogon raphides were not observed 
in the leaves but are common in the flower. In Baxteria and Kingia raphides were not 
observed in any tissues or organs; indeed, they appear to lack calcium oxalate entirely. 
In Xanthorrhoea raphides were not observed in material examined here, but 
rhomboidal calcium oxalate crystals or styloids are present in occasional mesophyll 
cells, bundle sheath cells and epidermal cells of some species of both Lomandra 
and Xanthorrhoea (Fig. 5d). 
