maize type was a heterozygous tunicate (7'w/tu) strain 
of Argentine popcorn. 
The material was prepared for staining by two tech- 
niques. One of these is asomewhat unusual method sim- 
ilar to that suggested by Cutler and Cutler (1948) as 
follows: 
Intact spikes (ears) were stained at the time of style 
emergence by placing their freshly cut bases in an aque- 
ous solution of safranin. In a few seconds this red stain 
had traveled up through the vascular system and had 
colored all of the xylem elements. Attempts to preserve 
this stained material by fixing it in (3:1) absolute alcohol: 
glacial acetic acid and then clearing it in a cedar wood oil 
series were unsuccessful because the color always diffused 
out from the bundles and into the adjacent, highly lig- 
nified rind; but, in less lignified material, such as that 
of typical maize, this clearing technique was successful 
in revealing the vascularization of specimens stained in- 
tact. It was later discovered that, if our stained speci- 
mens were immediately dried by warm, circulating air, 
the red color then remained in the bundles. Free-hand, 
three-dimensional drawings were then made from studies 
of the vascular system, as revealed on the exterior of 
these dried and intact specimens and as reconstructed 
from cross-sections of the same material. 
The other method used is a classical one. The material 
was fixed eighteen days after pollination, then dehydrated 
in an ethyl-alcohol series and embedded in paraffin for 
cross-sectioning and eventual staining. Although no diffi- 
culty was encountered with microtome sectioning in the 
case of the maize, the teosinte and T'ripsacum specimens 
were too highly lignified at this age for easy cutting. 
However, a few excellent free-hand sections of only about 
one cell-width in thickness were obtained from the em- 
bedded material of these relatives of maize. All sections 
[ 3 | 
