DEVELOPMENT AND DISTRIBUTION OF MUCILAGE CANALS IN LYCOPODIUM

Two distinct types of mucilage canals are found in Lycopodium. One type, the veinal canal, is found in both sporophylls and in vegetative leaves, and is always in close proximity to the leaf trace. The other, the basal canal, is restricted to the strobilus where it forms a complex and extensive mucilaginous cylinder in the outer cortex and extends into the base of the sporophylls. Protruding secretory cells are formed in both types during a lysigenous developmental process. The occurrence of these two types of canals correlates with the three subgenera. Urostachys which lacks canals, Lepidotis which possesses both veinal and basal canals, and Lycopodium which possesses only basal canals.