OPHIOGLOSSAGE^. 



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 OpMoglossaceee, 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 

 Botryehium Lunaria, 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 arehegonia 

 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, b' 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 Ophioglossiuem are 

 produced from mother-cells developed in ^-^^ 370.-Plant of Boi^chiwm 

 the tissue of the fertile segment of the iMnario, nat. size, si, «<, the short 



ia of 

 quite 



]p!if-bpnrH the nn rallpd SDnrnniria of ^t«" i f- rots ; 65, the leaf etnlk; 

 leal , nence me so-caiiea sporangia 01 ^^ ^o^a where the leaf hranches 



this order are morphologically 

 different from those of true Ferns. 



into the sterile part (6) and the fer- 

 tile or spore-bearing portion (/).— 

 After Sachs. 



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

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

 by Frederick Currey, London, 1863. 



f The vernation of our species qf Botryehium is well worked out iij 



