Development of the female flower and gynecandrous partial inflorescence of Myrica californica

Organogenesis of the female flower and gynecandrous partial inflorescence is described. Approximately 25 first-order inflorescence bracts are formed in an acropetal sequence. A second-order inflorescence axis, the partial inflorescence, develops in the axil of each bract. Third-, fourth-, and fifth-order axes arise in the axils of second-, third-, and fourth-order bracts. A gynoecium terminates a second-order axis and sometimes a distal third-order axis. A gynoecium consists of two stigmas and one basal, unitegmic, orthotropous ovule. The wall enclosing the ovule, the circumlocular wall, is comprised distally of gynoecial tissue and proximally of tissue of the inflorescence axis and its appendages. The latter portion of the wall is formed by zonal growth. Androecial members, formed proximal to the gynoecium on the partial inflorescence, are carried onto the circumlocular wall by zonal growth. A stamen may develop from the last-formed primordium before gynoecial inception or from a potentially stigmatic primordium. The papillae of the flower and fruit arise as emergences and from potentially bracteate, axial, and staminate primorida during the development of the circumlocular wall. The term circumlocular wall is used in a neutral sense to describe this unique structure. Since the gynoecium is composed of gynoecial appendages and inflorescence axis and appendages, a functional definition of gynoecium must be expanded to include any tissue, including an inflorescence, that surrounds the ovule(s) and forms the fruit(s).

Myricaceae: floral hypothesis for Gale and Comptonia

Organogenesis of the male reproductive structures of Myrica pilulifera, Gale, and Comptonia is compared. In M. pilulifera, which has a compound inflorescence, one to three stamens form in the axils of second-order bracts of the partial inflorescence. In Gale and Comptonia, which do not have compound inflorescences, four stamens arise simultaneously on the flank of the apex of the second-order axis. It is concluded that this defines a floral condition for the family. A model is proposed which explains the probable development of the floral condition from the inflorescence state more adequately than existing floral concepts. Hence, speculation of the phylogenetic status of this family is avoided. Similarly, it is not necessary to debate notions of an angiospermous archetype. Recent knowledge of the family is collated from various disciplines such as taxonomy, anatomy, and palaeobotany to provide a framework for assessing the significance of the discussion of the ‘flower’ vs. ‘inflorescence’ problem.