We have tested the hypothesis that reseeding is a plesiomorphic character s
tate and that sprouting is a derived state in Aspalathus linearis, and that
the latter is an adaptation to ensure fire-survival in a fireprone environ
ment. Samples of five seeder and four sprouter populations of A. linearis w
ere examined by horizontal starch gel electrophoresis to assess the amount
of genetic differentiation within and between sprouting and seeding populat
ions, and to determine the extent of gene flow between the populations. Lea
f extracts were surveyed for ten enzymes and gene products revealed genetic
variation at 13 (76%) of 17 protein coding loci. Allele frequency differen
ces were found between sprouting and seeding populations and genetic distan
ce values show that the sprouters are grouped separate from the seeders, th
us providing support for the morphological data on which the above mentione
d hypothesis is based. It is evident that evolution operates at the populat
ion level in A. linearis.