348 Dr. L. Radlkofer on Fecundation in the Vegetable Kingdom, 



Riccia are distinguished merely by their lower portion not be- 

 coming developed into a pedicel. 



Only Anthoceros possesses, according to Hofmeister and 

 Schacht, a structure of the archegonia aberrant from that hitherto 

 described. They do not appear here as organs isolated from 

 the rest of the cellular tissue, a particular row of cells of the 

 frondose stem, simply, becoming converted into the archegonial 

 canal. The cell lying immediately beneath this row assumes 

 the part of the central cell of an archegonium. 



Hofmeister found inside the calyx of Jungermannia bicuspidata 

 and divaricata, beside the just- opened archegonia, spermatozoids 

 still in motion ; motionless ones frequently in the mouth of the 

 archegonial canal*, and, according to his most recent publica- 

 tion t> still moving ones which had penetrated a third of the 

 distance down the archegonial canal in Funaria hygrometrica. 

 A similar statement is made by Schimper in respect to Sphagnum^, 



The development of the young plant of Mosses from the spore 

 was first observed by Hedwig ; more recently, by Nees v. Esen- 

 beck, Bischofi:, and, above all, by Gottsche, W. Schimper and 

 Hofmeister §. In the Mosses, it is not produced directly from 

 the internal cell of the spore, but through the intermediation of 

 a tissue of jointed confervoid filaments — protonema (pro-embryo, 

 Hofmeister). According to Hofmeister, these filaments are not 

 all of one kind, some appearing to correspond to stems, others to 

 leaves. The former only are capable of development, by the divi- 

 sion of their terminal cell by means of alternately inclined septa, 

 into bud-rudiments, sometimes bearing leaves and root-fibrils, 

 and thus of becoming the foundation of perfect Moss-plants. 

 When they penetrate into the soil, they acquire oblique septa, 

 and are destitute of chlorophyll, like the so-called roots of the 

 Mosses ; on the other hand, Nageli || and Schimper have observed 

 that the protonema-threads developed in the axils of leaves or 

 from the cells of leaves (aerial roots of authors), and even the 

 roots of Mosses, become green, form perpendicular cross-septa 

 and produce buds, in situations where they are exposed to the 

 light. 



In regard to the Liverworts, Hofmeister^s account of the de- 

 velopment at least renders the universal occurrence of a pro- 

 embryo doubtful^. Gottsche's opinion is to the same efiect **. 



* Vergleich. Unters. pi. 8. figs. 49 (properly 79) & 61, pi. 9. fig. 2. 

 pp. 37, 38. t Flora, 1854, p. 269. 



X Ann. des Sc. nat. 4 ser. i. p. 320 (1854). 



§ Op. cit. supra. 



II Zeitschr. f. wiss. Botanik, Heft ii. p. 168. Zurich, 1845. 



IF See also Hofmeister, Ueb. die Stellung der Moose in Systeme. Flora, 

 1852, p. 6. 



♦* Nova Acta A. C. L. C. xx. pt. 1. p. 386. 



