52 VASCULAR CRYPTOGAMS 



mature. Within the central cell are produced from twenty to two hundred 

 antherozoids, each in its own mother-cell. Both antherids and arche- 

 gones are deeply sunk in the tissue of the prothallium. The archegones, 

 only the uppermost part of the neck of which appears above the surface, 

 are formed on the ventral cushion, very rarely on the upper side of the 

 prothallium. Their development presents no very special features. 



The sporophyte generation has, when mature, the habit and appear- 

 ance of an ordinary fern. The stem is usually erect and short, with 

 tuberous base, never attaining a greater height than from one to two 

 feet ; less often (Kaulfussia, Bl.) a creeping underground rhizome. It 

 resembles the stem of OphioglossaceSe and Isoetese in never branching ; 

 that of true ferns in being densely covered, when erect, with leaves as 

 well as with roots, so that no portion is left exposed. The growing 

 point has a single apical cell, and is concealed in a terminal rosette of 

 large leaves. The fundamental tissue is everywhere traversed by long 

 rows of tannin-cells ; and lysigenous mucilage-cells 

 abound in the petioles and in the parenchyme 

 of the pith and cortex of the stem ; they anasto- 

 mose freely, and are continuous from the stem 

 into the roots. The sclerenchymatous tissue, so 

 characteristic of the parenchyme of the stem of 

 typical ferns, is but feebly developed, or is alto- 

 gether wanting, in the Marattiacese. The ' vascu- 

 ,,,.,,, lar ' bundles are concentric, and resemble those 



Fig. 70.— Base of leaf-stalk of ' 



Marattia. cut through, st, of truc fcms. A Central xylem, composed of wide 



stipule ; c, commissure ;z/, i-r i-i • iii 1 



anterior, h, posterior wing scalariform tracheidcs, IS surroundcd by the 

 (naturaisizeMAfterSachs:) phloem J the bundle-sheath is wanting in the 

 bundles belonging to the stem and leaves, but is present in those of the 

 root. The bundles bend from the stem into the leaves in the ordinary 

 way. The stem and rachis of the leaves are not covered with pales, as 

 in true ferns, nor are they completely glabrous, as in the Ophioglossacese. 

 The leaves are thick, coriaceous, and very large, attaining in some 

 species a length of from five to ten feet. They have a long and very 

 stout petiole, which is channelled on the upper side ; the lamina unfolds 

 very slowly, and is either simply or doubly pinnate, less often palmate 

 or digitate. They are furnished at their base with appendages peculiar 

 to the Marattiaceae among Vascular Cryptogams, the stipules or auricles. 

 While still in the bud the leaves are rolled up in a circinate manner, 

 and are entirely enveloped in the large stipules until the lamina unfolds. 

 The pair of stipules belonging to each petiole form an anterior and a 

 posterior chamber, separated from one another by a longitudinal wall 

 termed the commissure. In the posterior chamber is the rolled-up leaf 



