XVI International Botanical Congess
Cuticle micromorphology (CM) was examined in species of all genera of cycads except Microcycas and Chigua. Leaflets were obtained from greenhouse-grown plants at Duke Univ., Ohio Univ. and Cycad Connections, Queensland, Australia. Cuticles were isolated in 20% chromic acid and investigated using SEM. All species studied are hypostomatic and haplocheilic. CM varies widely in morphology but all species display internal stomatal polar extensions. CM patterns are generally consistent with curent cycad classifications. CM of Cycas is most similar to Stangeria and Bowenia, but differs somewhat from each of these. Ceratozamia and Zamia are similar in having a low flange surrounding guard cells, Encephalartos, Macrozamia,and Lepidozamia each possess a robust flange. CM suggests that Stangeria and Bowenia may not be as closely related as indicated by current classifications.