=Parts.=--_Integuments_, seed-coats. _Nucleus_, part containing the
embryo.
(1.) PARTS OF INTEGUMENTS:
_Testa_ (_episperm_), the outer or proper seed-coat.
_Tegmen_ (_endopleura_), the inner coat, sometimes wanting.
_Funículus Hílum_ (_h_), _Chalāza_ (_c_), _Rhāphe_ (_r_), are the same
as in ovule.
_Aril_, covering exterior to the integuments (not in the ovule)
(May-apple, Water-lily).
_Coma_, [Illustration] a tuft of hairs on certain seeds (Silkweed).
This is to be distinguished from pappus, which is a tuft on the fruit
(Achenium).
(2.) PARTS OF NUCLEUS: [Illustration]
_Embryo_ (_e_), the initial plantlet.
_Radicle_ (_r_), [Illustration] the rudimentary stem or first internode.
_Cotylēdon_ (_c_), the seed leaf at the primary node.
_Plūmule_ (_p_), the growing points above the cotyledons.
_Albūmen_ (_a_), [Illustration] the food for the plantlet’s first
growth, stored outside the embryo.
=Kinds.=--(1.) GENERAL FORM: _Orthotropous_, [Illustration];
_campylótropous_, [Illustration]; _anátropous_, [Illustration];
_amphítropous_, [Illustration] same as in ovule.
(2.) FORM OF COVERING:
_Conformed_, adhering closely to nucleus.
_Cellular_, loose (Pyrola).
_Winged_, [Illustration] having expanded appendages (Catalpa).
_Woolly_, covered closely with fibers (Cotton).
_Cōmose_, [Illustration] with coma at the end (Willow Herb).
(3.) TEXTURE OF ALBUMEN:
_Farinaceous_, mealy (Wheat).
_Oily_, mealy but mixed with oil (Poppy).
_Muciláginous_, like mucilage (Morning-glory).
_Ruminated_, wrinkled (Papaw).
(4.) NUMBER OF COTYLEDONS:
_Monocotylédonous_, [Illustration] (Corn).
_Dicotylédonous_, [Illustration] (Bean).
_Polycotylédonous_, [Illustration] (Pine).
(5.) POSITION AND ARRANGEMENT OF EMBRYO:
_Eccentric_, [Illustration] embryo on one side of albumen (Indian Corn).
_Perípheric_, [Illustration] curved around albumen (Four-o’clock).
_Accumbent_, [Illustration] applied to the cotyledons when the radicle
is bent and lies along their edge (Water-cress).
_Incumbent_, [Illustration] applied to the cotyledons when the radicle
rests against the back of one of them (Shepherd’s Purse).
_Conduplicate_, [Illustration] applied to cotyledons that are incumbent
and so folded as to embrace the radicle (Mustard).
(6.) THE DIRECTION OF THE EMBRYO AS RESPECTS THE PERICARP.
_Ascending_, pointing to the apex.
_Descending_, pointing to the base.
_Centripetal_, pointing to the axis.
_Centrifugal_, pointing to the sides.