Rudall & Chase, Systematics of Xanthorrhoeaceae sensu lato 
641 
In the commelinoid clade, silica bodies may be either epidermal or present in the 
bundle sheath. Epidermal, spherical (druse-like) silica bodies, similar to those of 
Kingia and Baxteria, are found in Bromeliaceae, Zingiberaceae, Cyperaceae and 
Thurniaceae, and also Rapateaceae, where silica bodies may be solitary or numerous, 
or in the form of fine sand (Tomlinson 1969). Spherical silica bodies occur in various 
other commelinoid monocots, such as Arecaceae, Cannaceae, Costaceae, Marantaceae, 
Musaceae and Strelitziaceae, but usually in the bundle sheath cells adjacent to 
sclerenchyma, never in the epidermal cells. 
a 
b 
c 
d 
Fig. 5. Presence or absence of silica in epidermal cells. Left: SEM micrographs of cross sections; right: 
corresponding maps representing density of silica in regions photographed (highest densities of 
silica indicated white), a, Bnxterm australis: spherical silica body; b, Kingia australis: spherical silica 
body; c, Dasypogon bromcliifolius: silica sand; d, Xauthorrhoca minor: silica absent. Scale bars = lOgm. 
