OPHiOGLOSSAOJE^. 



379 



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

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

 of species probably does not exceed twenty-five. 



Tlae 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- 

 pliyll ; they develop underground, and 

 are difficult to study, hence they are 

 known for' but few of the species. In 

 Botrychium Lunarin, according to Hof- 

 meister* tlie 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. 368). 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, h' and 6", and Fig. 

 370). 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 Ophioglossacece are 

 produced from mother-cells developed in j,jg_ ^o.-PIant of Botrychivm 

 the tissue of tbe fertile segment of the XwwaHa, nat. size, si, s^, the short 

 1 .* 1, J.-I, n J ■ t Btem : w. rnots ; bs, the leaf stalk : 



leaf ; hence the so-called sporangia of ^^ po'int where the leaf branches 

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

 j.«. .J, ^1 i^ c " tile or spore-bearing portion (/).— 



different from those of true Ferns. 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 of Botrychium is well worked out in 



