TABLE 3.

Key for Prototheca differentiation^a

Feature	P. wickerhamii	P. zopfiib	P. blaschkeae	P. stagnora
Colony morphology	Hemispheric, with smooth margin	Flat, rough, central button, corrugated margin	Flat, smooth, central button, corrugated margin	Flat, with smooth margin
Diameter of cells (μm)	3-10	7-30		7-14
Glycerol assimilation	+	+	−	+
Growth on:
Sucrose	−	−		+c
Trehalose	+d	−	−	−
n-Propanol	−	+		−
Arginine	+	+	−	+
Dextrose	+	+	+	+
Galactose	±	±		+
Clotrimazole (50 μg)	−e	+		+
Growth at 37°C	+	+	+	−
Capsule	−	−	−	+

^aAdopted according to the data in references 119, 125, 126, and 141. +, positive; −, negative; ±, strain variation.

^bCurrently includes two genotypes.

^cAssimilation within 14 days.

^dAssimilation within 7 days.

^eProduction of inhibition zone.