48 MINNESOTA BOTANICAL STUDIES. 



forms spiral granulations; these become the elaters. Rarely 

 (as in Riella) they are replaced by barren cells filled with food 

 material for the nutrition of the growing spores. The two 

 kinds of cell are equal in number, each alternating with the 

 other." 



Kienitz - Gerloff found the measurement of ripe elaters of 

 Marchantia polymorpha to be .55 mm. 36 Leitgeb gives the 

 length of elaters in CyathodiumF as . 36 mm. Schiffner^s states 

 that the elaters of Radiila pi^otensa Ldnb., var. irrectilobula are 

 .2 mm. long and .0048 mm. thick. 



Erroneous figures of Marchantia elaters are shown in Le 

 Maout et Decaisne, Traite de Botanique. 704 (1876), and re- 

 peated in Bessey, Botany for High Schools and Colleges. Ed. 

 VI. (1889), andBastin, College Botany. 341. (1889). 



Correct figures of Marchantia elaters are shown in Sachs, 

 Text-book of Botany. Ed. II. 355. (1882), and repeated in Goe- 

 bel, Outlines. Eng. Trans. 159. (1887), and Van Tieghem, 

 Traite de Botanique. 2:1343. (1891). Also, correct figures are 

 shown in Leitgeb, loc. cit. Heft V. Tof. IIT, fig. 8. 



The branching of elaters of any kind has scarcely been 

 touched upon. In the Micrographic Dictionary it is stated 

 that Targionia has branched elaters^*^ and a figure of a branched 

 elater is given. ^^ Branched elaters of Trichia, one of the slime 

 moulds, are shown in Pringsheim's JahrbUcher, which resemble 

 somewhat those of ConocephalusJ^ Underwood*- states that 

 Anthoceros has simple or branched elaters. Schiffner*^ notes 

 that the elaters of Badula protensa Ldnb. are often branched 

 and a representation of one is given. 



Original investigations. The fact that branching occurs in 

 the elaters of Gonocephalus conicus was noticed by Mr. A. M, Mur- 

 fin in specimens of this plant brought into the morphological 

 laboratory of the University of Minnesota for class work. It was 

 then too late in the season to obtain other material for compar- 

 ison, so that it is not known whether or not the same thing oc- 

 curs in other Minnesota genera of the Marchaniiacece. 



36. Kienitz- Gerloff, loc. clt. I'Jl. 1874. 



37. Leitgeb. loc. cit. Hefl VI. 138. 1879. 



38. Schiffner, loc. cit. 247. 1893. 



39. Griffitli and Henfrey, Microg. Diet. Ed. II. 1:348. 1860. 



40. Grifflthi and Henfrey, Microg. Diet. Ed. II. 1: 677. figs. 720. 723, 734. 1860. 



41. Wigand, Zur Morph. u Syst. d. Gatt. Trichia u. Areyria. Jalirb. f. wiss. Bot. 

 Pringsh. 3: Ta/. /. fig. 10. 1863. 



42. Underwood, Gray's Man. Ed. VI. 726. 1889. 



43. Schiffner, loc. cit. 247. Taf. VII. 1893. 



