=Kinds.=--(1.) PRIMARY, growing from root-end of embryo.
(a.) SIMPLE.--_Conical_, [Illustration]; _napiform_, [Illustration];
_fusiform_, [Illustration].
(b.) MULTIPLE.--_Moniliform_, [Illustration] necklace-like.
_Fasciculated_, [Illustration] tufted, thick and fleshy. _Tubercular_,
[Illustration] having small tubers. _Fibrous_, [Illustration]
threadlike.
(2.) SECONDARY, growing from stems.
_Underground_, starting from stem below ground. _Aerial_, starting from
stem above ground.