OPHIOGLOSSACE^. 



379 



found in the tropical regions of the eastern hemisphere ; and Marattia, 

 which is represented in the New and Old World. The whole number 

 of species probably does not exceed twenty-five. 



The oldest members of this order oc- 

 cur in the Permian strata. 



Order Ophioglossaceae, the Adder- 

 Tongues. The prothallia of these fern- 

 like plants are thick masses of paren- 

 chyma, which are destitute of chloro- 

 phyll ; they develop underground, and 

 are difficult to study, hence they are 

 known for but few of the species. In 

 Botvychium Lunaritt, according to Hof- 

 meister,* the prothallium is "an oval 

 mass of firm cellular tissue, whose larger 

 diameter does not exceed a millimetre 

 (one twenty-fifth of an inch), and is often 

 less" (Fig. 268). He discovered them 

 in the ground at a depth of from two 

 and a half to seven and a half centim- 

 etres (one to three inches). The an- 

 theridia occur for the most part upon 

 the upper surface, and the archegonia 

 upon the lower. 



The mature plant (asexual generation) 

 consists of a short erect underground 

 stem, which bears annually one or more 

 stipulate and erect (i.e., not circinate)f 

 leaves (Fig. 269, &' and b", and Fig. 

 270). The leaf is usually divided into 

 two portions, one of which is green and 

 expanded (Fig. 270, b), while the other 

 is contracted into a spore-bearing organ 

 (Fig. 270, /) ; in some cases each seg- 

 ment is simple, while in others it is one 

 or more times compound. 



The spores of the Ophioglosaaceai are 

 produced from mother-cells developed in 



the tissue of tlie fertile segment of the Lun ana, nat. size, st, st, th'e short 

 leaf; hence the so-called sporangia of JW'Jffi ft ^ftiESi 

 this order are morphologically quite into the sterile part (6) and the fer- 

 different from those of true Ferns. 



Pig. 270.-Plant of Botrychium 



* " On the Germination, Development, and Fructification of the 

 Higher Cryptogainia," etc., by Dr. Wilhelm Hofmeister. Translated 

 by Frederick Currey, London, 1862. 



f The vernation of our species of Botrychium is well worked out iu 



