Events Of Sexual Reproduction

The ovule in which the funicle, chalaza and micropyle lie on one vertical plane is called orthotropous (GK. orthos = straight; trope turned). In this type, the body of ovule is straight. Hilum and chalaza occur nearly. It is also called atropous or erect ovule, e.g., Piperaceae, Polygoniaceae, Uricaceae, etc. It is the most primitive and simplest type of ovule in angiosperms.