Breakdown of distyly
and pin-monomorphism in Psychotria carthagensis.
Distyly in Amsinckia conforms to the classic one-locus genetic model (Ganders 1979) in which the short style-long stamen floral morph (thrum) is dominant to the long style-short stamen morph (pin).
On the basis of morphological and chromosomal evidence, Ray and Chisaki (1957a) suggested that distyly has been lost independently in at least four lineages of Amsinckia.
and variation in heteromorphic incompatibility in Gaertnera vaginata (Rubiaceae) endemic to La Reunion Island.
in Erythroxylum undulatum from northern Venezuela.
For example, models of the evolution of distyly conflict as to whether heteromorphic incompatibility evolves before reciprocal herkogamy (Charlesworth and Charlesworth 1979) or after it (Lloyd and Webb 1992a,b).
Their work suggests that there were multiple shifts from distyly to homostyly in the genus, and they found little evidence of either great longevity of selfing lineages or speciation within these lineages.
spectabilis 5 Phylogenetic lineage Population douglasiana/gloriosa Paloma Creek Canyon Lockwood Paloma Creek Canyon New Idria spectabilis Nipomo Lompoc Lompoc 17 Alisal Slough Zmudowski State Beach Floral morphology Phylogenetic lineage Flower size Distyly
douglasiana/gloriosa Large Heterostylous Large Heterostylous Small Homostylous Small Homostylous spectabilis Large Heterostylous Large Heterostylous Large Homostylous Small Homostylous Small Homostylous
We have previously explored the genetic basis of breeding-system variation, the origin of self-compatibility from distyly
, and the potential for fertility assurance and its floral correlates (Shore and Barrett 1985, 1990; Barrett and Shore 1987).
The evolution of dioecy from distyly
: reevaluation of the hypothesis of the loss of long-tongued pollinators.
On the genetic consequences of distyly
and self-incompatibility in Anchusa officinalis L.