2i8 The Ohio Naturalist. [Vol. II, No. 5, 



cases as the Pine the tissue which surrounds the embrj-o can be 

 called what it actually is, the female thallus or female gametophyte 

 filled with food material. 



The term root must be restricted to the sporophyte generation 

 and root-hairs to hairs on real roots. The terms rhizoid and hold- 

 fast may be used for similar organs of the gametophyte. The 

 word leaf should be restricted entirel}^ to the sporopyte. Any 

 reduced leaf ma}' be called a bract or scale-leaf. For expansions 

 on the gametophyte the term scale ma}' be used as moss scale, 

 liverwort scale, scaly Liverworts, etc. Expanded thalli, as those 

 in many of the red and brown Algae, and lyiverworts and Messes 

 may be called fronds. There is no need of calling a fern leaf a 

 frond. It is of the same nature as the leaf of a seed plant and 

 .should have the same terminology. The term stoma should be 

 used only for true stomata on the sporophyte. Passages of some- 

 what similar function, but not similar structure on the gameto- 

 phj'te of some Liverworts ma}^ be called air passages for want of 

 a better term. It would be well to drop the term prothallus in 

 the Pteridopln'tes and call the gametophyte, what it really is, 

 simply a thallus. The term germinate should be restricted to 

 the division or budding of cells and spores ; it should not be used 

 for the breaking out of the embryo plant from the seed. This 

 process should always be called .sprouting. There is not even au 

 analogy between this process and the germination of the spore. 



The terms photosynthesis, digestion, respiration, and assimila- 

 tion .should be properly applied, especially assimilation, which 

 should refer only to the conversion of dead food materials into 

 living protoplasm. It would be ver}^ fortunate if the terms 

 daughter cell, mother cell, and grandmother cell would always be 

 applied to successive generations of cells produced by division. 

 Thus in the formation of the spores on the sporophyte, the cells 

 which are differentiated and usually separated from the general 

 tissue are spore grandmother cells. These divide into two to 

 form the two spore mother cells, which again divide, thus form- 

 ing the four daughter cells which develop into the spores. The.se 

 grandmother cells are usually called spore mother cells, but it is 

 better to use the term sporocyte, and if there are two kinds of 

 spores, the cells may be called microsporocytes and mega- 

 sporocytes. 



These are only a few of the most important terms that might 

 be defined, but if these alone were always correctly applied, 

 amateur students as well as those more advanced might obtain a 

 clearer conception of the subject with much less outlay of misdi- 

 rected effort. 



