Structure and Symmetry of Species of the Sphaeradenia Group (Cyclanthaceae): Stelestylis stylaris, Sphaeradenia woodsonii, and Ludovia spp.

Abstract

S. stylaris, S. woodsonii and the 3 spp. of Ludovia [L. lancifolia, L. bierhorstii and L. integrifolia] exhibit the 2nd of 3 main types of growth habit among cyclanths. Individual monopodial vegetative axes produce vegetative branches and inflorescences solely from lateral buds. Flowering is always pleonanthic. In each species an adult leaf may subtend only 1 inflorescence; S. stylaris also produces clusters of 2, and L. lancifolia, 3 axillary inflorescences. In such clusters an inflorescence produced after the first-formed one develops axillary to a peduncle sheath. In S. woodsonii a small supernumerary bud sometimes, but not always, occurs at the base of an inflorescence, abaxially just beneath the inflorescence prophyll. In all species first-order vegetative buds and inflorescence buds may grow outward from a leaf axil without substantially damaging the subtending adult leaf. In L. bierhorstii each type of expanding lateral bud may also grow out through the base of the adult leaf. Stems of each species bear adventitious roots. S. stylaris exhibits substantial dorsiventral symmetry and mirror-image symmetry.