New and unusual forms of calcium oxalate raphide
crystals in the plant kingdom.
The presence of idioblasts with raphides
on the leaf blade margins of S.
1992) found that starch granules from various plant species could be differentiated based on their morphological attributes (including size, overall shape and the appearance of any facets) and the co-presence or absence of raphides.
Preliminary identification of the residues, which include starch granules and raphides, indicates they are of likely aroid origin, most probably Colocasia esculenta (taro).
Starch granules and raphides were present on all 20 sherds, in clusters and lighter scatters (Figure 2).
Based on the size and overall shape of the granules and the co-presence of raphides it is suggested that the residues are from C.
Raphides and druses had generally retained their high visibility and pleochroism (shifting colour zones) when viewed under cross-poladsed light.
Starch grains are highly concentrated in the stems, whereas calcium oxylate crystals and xylem are found throughout the plant, with raphides in particular often in very high concentrations.
Microfossil evidence of possible food plants associated with Lapita from the Bismarck Archipelago includes starch grains and raphides of Colocasia esculenta, identified in New Ireland (Crowther 2002).
Along with raphides, druses and crystal sand occur nearly universally.
Alternatively, in elongated cells, there may be two or more separate bundles of raphides.
Given the broad array of crystal bundle and cell types for raphides in this family, clear trends of specialization might be expected, but they remain unexpectedly obscure (Keating, in press a).