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. The leaves of the
   endogens have, usually, parallel veins, their flowers are mostly in
   three, or some multiple of three, parts, and their embryos have but a
   single cotyledon, with the first leaves alternate. The endogens
   constitute one of the great primary classes of plants, and included all
   palms, true lilies, grasses, rushes, orchids, the banana, pineapple,
   etc. See Exogen.