THE FERN. 



N7 



PLATES XXI., XXII. 



THE FEEN. 



a. Archegonium. 



a . Neck of the same. 



ii.fi. Apical cell. 



tin. Anniilus. 



up. Growing apex of stem. 



a/*'. Growing apex of leaf. 



at. Antberidium. 



at'. Parent cell of the same. 



az. Parent cells of antherozooids. 



h.c. Basal cell. 



c. Cilia (for Fig. XIII. PI. XXII. Cushion). 



ca. Ventral canal cell. 



t-a'. Central cell of neck. 



c.e. Central cell. 



cl. Chlorophyll grains. 



cl. Cotyledon. 



/. So-called foot. 



i. Indusium. 



i.e. Investing cells of sporangium. 



;..i. Intercellular space. 



/. Leaf stalk (rachis). 



/'. Leaflet. 



l.li. Lateral bud. 



/./. Lateral line. 



nix. Mesophyll. 



nc. Nucleus. 



n.c. Dividing neck cell. 



or. Oosphere. 



p. Pinna. 



l>c. Parenchyma. 



pc'. Conjunctive parenchyma. 



p.p. Protophloem of Russow. 



pt. Prothallus. 



r. Roots. 



r'. Root hairs. 



r". Primary root hairs. 



r/i. Rhizome. 



r.j>. Primary root. 



d. Sclerenchyma. 



scl'. Peripheral sclerenchyma. 



id". Central sclerenchyma. 



s;/. Ripe sporangium. 



si/'. Young sporangium. 



xh. Bundle sheath. 



ah'. Phlrem sheath. 



/>. Spores. 



up'. Spore mother cells. 



*./>. Sieve plate. 



*{. Stoma. 



s.t. Sieve tube. 



tc. Trichomes. 



tji. Tupetum. 



nt. Protoplasmic utricle. 



v.b. Vascular buudlc. 



v.b'. Peripheral bundles. 



v.b". Central bundles. 



re. Vacnole (cell sap). 



xy'. Protoxylem vessels. 



xij". Scalariform vessels (secondary xylem). 



