SECT. I 



CRYPTOGAMS 



449 



(Fig. 393, A-0), as do also the archegonia (Fig. 394, A-C). Tlie slightly projecting 

 neck of the latter opens after the neck-canal-cell has swollen and disintegrated ; 

 the oosphere (o) remains in the sunken venter. In many species the embryo leads 

 a subterranean existence for several years. The primary root is first formed and 

 soon projects from the archegonium (Fig. 392, C, k) ; later the first leaf and the 

 apical cell of the stem are differentiated. In some species of Botrychium the 

 embryo forms an elongated multicellular suspensor at the end of which the proper 

 embryonic mass is formed (^'^^). In this an agreement with the Lycopodinae is 

 evident (cf. Fig. 412 and Fig. 417). 



Fig. 393. — Ophioglossum fulgatuiit. A-C, fita^as 

 in the development of the antlieridium from 

 a superficial cell ; the upper cell in C gives 

 rise to the cover-cells, the lower to the 

 mother -cells of the spermatozoids. D, 

 Antheridiuni not yet opened ; <?, cover-cells. 

 E, Spermatozoids. (After Brcchmann.) 



Fio. 394. — O'lMoijlossum vuhjatum. A-C, De- 

 velopment of archegonium ; D, mature opened 

 archegonium with two spermatozoids (s) in 

 front of the opening ; h, neck -cells ; til; neck- 

 canal-cells ; 0, egg-cell ; h, basal cell. (After 

 Bruchmann.) 



Order 2. Marattiaceae 



This order includes a number of stately tropical Ferns with thickened tuberous 

 stems and iisually very large leaves provided with two stipules at the base. 

 The sporangia are situated in groups (sori) on the under surface of the leaves, 

 and are either free {AngioiHeris), or united to form an oval capsule-like body, the 

 chambers of which are the sporangia. The prothallium in contrast to that of the 

 Ophioglossaceae is a green, heart-shaped thallus, resembling that of a Liverwort 

 and growing on the surface of the soil. It is sometimes dichotomously branched. 

 The sexual organs resemble those of the preceding order but are developed on the 

 lower surface of the prothallus. An endophytic fungus occurs in the cells of the 

 prothallus ('-'). 



Sub-Class II. Leptosporangiatae 



Order 1. Filices 



The Filices, or Ferns, in the narrower sense of tlie word, comprise a large 

 number of genera with numerous species, being widely distributed in all parts of 

 the world. They attain their highest development in the tropics. The Tree- 

 Ferns {Cyaihea, Alaoiildla, etc.), which include the largest representatives of 

 the order, occur in tropical countiiCS, and characterise the special family of the 

 Cyatheaceae. The stem of a Tree-Fern (Fig. 395) is woody and unbranched ; it 



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