Rudall & Chase, Systematics of Xanthorrhoeaceae sensu lato 
643 
Pollen and ovules Both pollen and ovule characters have proved to be taxonomically 
useful in asparagoids (e.g. Chase, Rudall & Conran, in prep.). Chanda & Ghosh (1976) 
examined the pollen morphology of Acaiithocarpiis, Baxteria, Calectasia, Chamaexeros, 
Dcisppogoit, Kingin, Lotnancira and Xanihorrhoeci, but found no significant apomorphies, 
apart from similar sulculate grains in Acaiithocaipus and Chamaexeros, and punctate 
surface sculpturing in Dasypogou and Kingia (Table 5). Baxteria has a unique 
unipantocolpate pollen type, with reticulate surface sculpturing (as in Calectasia). The 
large genus Lomandra is palynologically diverse. It includes three species (L. endlichcri, 
L. leiicocephala, L mierantha) with spiraperturate grains, which led Chanda & Ghosh 
(1976) to suggest that these species should be segregated into a separate genus, although 
according to Stevens (1978) there is no anatomical or morphological evidence to support 
this. Spiraperturate grains occur in a few unrelated groups, both dicots and monocots 
(Furness 1985), including some Eriocaulaceae, Costaceae, Crocus (Iridaceae) and also 
the isolated genus Apin/llauthes. They may be derived from sulculate types (Chandra 
& Ghosh 1978) or inaperturate types (Furness 1985). Pollen of other putatively related 
arthropodioid genera, such as Thysanotus, would merit further investigation. 
Rudall (1994) described the ovule and embryo sac in Xanthorrhoeaceae sensu lato, 
and recorded in Lomandra a markedly enlarged chalazal dermal layer of the nucellus, 
usually associated with large antipodals, which also occurs in other members of the 
recircumscribed family Lomandraceae: Artliropodium, Chamaexeros, Dichopogon, 
Eustrephus, Sowerbaea and Thysanotus. The massive starchy nucellus in Calectasia and 
Dasypogon differs from the nucellus types found in asparagoid taxa. The formation 
of the micropyle by the inner integument alone (Table 4) is also apparently an 
asparagoid character. 
Taxonomy 
Anatomical, embryological and molecular data indicate that Xanthorrhoeaceae sensu 
lato (Bedford et al. 1986) is a polyphyletic assemblage, with at least four generic 
groupings; (1) a Lomandra group (Acanthocarpus, Chamaexeros, Lomandra, Romnalda 
and Xerolirion), (2) Xanthorrhoea alone, (3) Dasypogon and Calectasia and (4) Kingia 
and Baxteria. These correspond closely to Fahn's (1954) anatomical groupings. The 
former two are asparagoid, the latter two commelinoid. Since their relationships are 
so broad, it is inappropriate to carry out a cladistic analysis here, as this would 
require comprehensive comparative data on many other monocot groups. However, 
with the existing data we propose that the ten genera of Xanthorrhoeaceae sensu lato 
be distributed in three recircumscribed families: Dasypogonaceae (Baxteria, Calectasia, 
Dasypogon and Kingia), Lomandraceae (Acanthocarpus, Chamaexeros, Lomandra, 
Romnalda and Xerolirion, together with other genera: Chase, Rudall and Conran in 
prep.) and Xanthorrhoeaceae sensu Dahlgren et al. (1985) (Xanthorrhoea). 
Dasypogonaceae Dumort. (1829) 
New circumscription. Genera included: Baxteria R.Br. ex Hook., Calectasia R.Br., 
Dasypogon R.Br., Kingia R.Br. 
On the basis of rhcL analysis (Chase et al. 1995a), cell wall ferulates (Rudall & Caddick 
1994), and presence of silica (this paper), Dasypogon, Calectasia, Kingia and Baxteria 
(Dasypogonaceae) belong in the commelinoid clade (Fig. 6) (Table 5). Dasypogon and 
Calectasia are similar to each other in several respects: vascular bundle structure, 
branched trichomes and stomata (Fahn 1954, this paper) and especially in ovule 
morphology (Rudall 1994) (Table 5). Kingia appears close to Baxteria on the basis of leaf 
anatomy, silica grain morphology (druse-like; this paper) and presence of substomatal 
cells (Fahn 1954). Since the family Dasypogonaceae sensu Brummitt (1982) comprised 
