46 MINNESOTA BOTANICAL STUDIES. 



tion of spores and elaters in FruUania, Lejeiinia and Blasia.^ 

 GoebePO states: "In the majority of the Hepaticae a number 

 of sterile cells occur, and these figure either as nourishing cells 

 of the spore mother-cells, which last gradually absorb the ma- 

 terial stored up in the first; or they become spindle-shaped 

 elaters provided with spiral thickenings to which belong in the 

 sowing the loosening of the complex spores." And again: 

 "But not all become spore mother-cells: a part remain sterile 

 and at first are filled with starch-grains which are consumed 

 during the growth of the spore mother cells." He goes on to 

 say that also in Biella sterile cells are found in the sporogonia 

 among the spore mother- cells, which remain with thin walls, 

 the so-called nourishing cells of the spore. Insignificant spin- 

 dle forms are found in Corsinia. Boschia has undoubted elaters 

 — long cells mostly with brown ringed or spiral thickenings 

 which are hygroscopic and have the function of loosening the 

 spore mass when ripe and tiius releasing the spores. ^^ Leclerc 

 du Sablon^^ gives a very complete description of the relative 

 arrangement of the spores and elaters in a number of genera. 

 In FruUania dilatata he states that "the disposition of the 

 spores is not less regular than that of the elaters, and there 

 are as many vertical rows of spore tetrads as there are of 

 elaters. The sporogoniuni being somewhat spherical, it is evi- 

 dent that all the elaters are not of equal length; those which 

 are near the central part are the longest, and their length di- 

 minishes as they depart from the axis." In the case of Pellia 

 ■epiplnjlla he observes that the elaters upon the periphery are 

 disposed irregularly; towards the interior a felting of spores 

 and elaters is formed, and in the center there is a sort of col- 

 umella made up exclusively of vertical elaters. In Targionia 

 hypophyUa the disposition of spores with relation to elaters is 

 very irregular and appears always the same whatever section 

 is considered. On the periphery of the sporogonium there is 

 found a continuous bed of elaters. Sterile cells are present in 

 Sphaerocarpus terrestris. The role which one generally at- 

 tributes to them is that of nourishing the spores. It is, how- 

 ever, more exact to compare them to spore mother - cells 

 arrested in their development. The same writer has thorough- 

 ly investigated the development of the spores and elaters. In 



29. Leitgeb, loc. cit. Heft III. 30. 1874. 



30. Goebel, Die Muse, in Schenck Handb. Bot. 3 : 317. 1882. 



31. Goebel, loc. cit. 3 : 353. 1882. 



32. Leclerc du Sablon, Rechr. sur le dev. du Sporog. des Hep. Ann. Sci. Nat. 7 ser. 

 11, 130. 1885. 



