endogen

1. (botany) A plant which increases in size by internal growth and elongation at the summit, having the wood in the form of bundles or threads, irregularly distributed throughout the whole diameter, not forming annual layers, and with no distinct pith.Examples: "The endogens constitute one of the great primary classes of plants, and include all palms, true lilies, grasses, rushes, orchids, the banana, pineapple, etc."