Morphogenetic Studies on the Inflorescence of Cotton

Abstract

1. The ontogeny and development of the main axis, the fruiting branch, and the flower of three varieties of cotton are described. The vascular anatomy of the flower is also given. 2. The main stem consists of a single indeterminate primary axis from which leaves, stipules, and branches arise in acropetal succession from a terminal meristem. 3. The fruiting branch develops sympodially, and consists of a series of single internodal axes. As each axis is terminated by a flower, a new bud arises to continue the branch. This process is repeated each time a flower is formed. 4. From the flower primordium there arise three bract primordia, a sepal zone, a common petal-stamen zone from which stamens and petals are diverged almost simultaneously, followed by the carpel primordia in the order named. 5. The anomalous staminal column is developed from a basic number of five stamens, each proliferating to form a considerable number of stamen primordia on each of the five lobes of the column. Branching of stamen primordia further increases the number of stamens. 6. Three traces supply the nodes on the main axis and branch axes. 7. The vascular cylinder of the flower becomes anastomosed in the toral region. From this there is successively diverged: first, six bundles to the bracts, then the adaxial carpellary system, followed by the abaxial carpellary system at a higher level; next, five or more bundles supply each sepal, three or more bundles to each petal, and finally ten main bundles to the staminal column.