papyrescent condition in Sorghum, where it once led to 
the describing of a new species (Sorghum papyrascens 
Stapf), an error later corrected by Rangaswami and 
Panduranga (1986) who correctly identified it as a single 
gene mutant characterized by defective glume develop- 
ment. Papery glumes have also appeared in two X-ray 
induced mutants (seminudoides and subnudoides) of bar- 
ley (Scholz, 1956). In these two recessive mutants, the 
floral bracts fragmentize away from the grain during 
threshing. Ordinarily the floral bracts of barley remain 
about the grain following threshing, except in the mutant 
named nudoides. The differences in the terminology of 
Sholz and Andrés, as applied to their particular mutants, 
refer to differences in the normal condition of the glumes 
in barley and maize. The term ‘‘seminudoides”’ (half- 
nude) applies to the barley mutant because normally the 
threshed barley grain is completely covered, while ‘‘semi- 
vestidos”’ (half-clothed) is better for the maize mutant 
because normally the maize grain is exposed. 
Papyrescent glumes in maize consist largely of non- 
specialized parenchyma-cells which, at 18 days from pol- 
lination, are large and fleshy, being swollen with water 
(Plate X, fig. 1). During final maturation of the ear, 
dessication causes these parenchymatous glumes to shrink 
to athin, almost transparent condition with the vascular 
bundles becoming prominent ridges (Plate LX, fig. 1). 
There is little contraction in length and width, however, 
and the glumes remain partially covering the surface of 
the mature grain. Finally, they become papery and brit- 
tle and are distinctly different from those glumes which 
protect the caryopses of other grasses. 
The epidermal layers of the papyrescent glume ap- 
proach those of the normal glume in regard to cell size, 
but differ from normal in being less lignified and in lack- 
ing stomata. Pubescence is usually confined to the mar- 
[ 65 ] 
