504 



BOTANY 



PART II 



Order 2. Ophioglossaceae ( m ) 



European examples of this order, which contains only a few species, are afforded 

 by Ophioglossum vulgatum, Adder's Tongue (Fig. 467 E), and Botrychium, Moon- 

 wort (Fig. 467 A], Both have a short stem, from which only a single leaf unfolds 



FIG. 467. A, Botrychium lunaria. Sporophyte. ( nat. size.) B, Transverse section of the pro- 

 thallus ; an, antheridium ; ar, archegonium ; em, embryo; en, fungal hyphae (x 45). C, 

 Prothallus bearing two embryos, the roots of which have emerged (x 16). D, Embryo with 

 the first and second roots (w lt ic 2 ) and foot (/) (x 16). E, Ophioglossum vulgatum. Sporophyte 

 showing the bud for the succeeding year. ( nat. size.) F, Ophioglossum vulgatum. 

 Prothallus. an, antheridia ; ar, archegonia ; fc, young plant with the first root; ad, 

 adventitious branch; h, fungal hyphae. (x 15. B-D, F after BRUCHMANN.) 



each year. The leaves in both cases are provided with leaf-sheaths. In Ophioglossum 

 the leaf is tongue-shaped, in Botrychium it is pinnate. These leaves bear on their 

 upper side a fertile segment arising near the upper end of the leaf-stalk. This 

 fertile segment in Ophioglossum is simple and cylindrical, with the sporangia sunk 

 in two rows ; in Botrychium, it is pinnately branched in the upper part, and 



