The Pentacyclidce. 
155 
emerges, determined by a tendency to the uniovulate condition. 
Sympetaly arising from the former (main) line leads to the Primu- 
laceae and Myrsinaceae: sympetaly arising from the latter (branch) 
line leads to the Plumbaginaceae. 
mRS\N*C ZPL PRlMULACE/t 
A faint trace of a tendency to epigyny appears in the caryo- 
phylline stock,—e.g., Portulaca, Beta ; this is reflected in the 
Primulales in Mcesa, Glaux, and Samolus. Unlike the Vaccinioideae, 
derived, we suggested, from a plexus characterized by a definite 
and general tendency to epigyny, the Primulales have made no 
advance in this direction, but have retained the hypogynous 
arrangement in the great majority of their species. 
General progressive adaptation to insect visits among the 
Primulales has halted, broadly speaking, at sympetaly ; zygomorphy 
is unknown, except in the aberrant genus Coris, comprising but one 
or two species, occurring in the Mediterranean region. Special 
adaptation is found in the form of heterostyly—a phenomenon 
which has been familiarized by the well-known example of Primula ; 
but how far this is so general a feature of the cohort as to be 
regarded as a distinctive character needs investigation. 
