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



on the pedicels of the spore-capsules of many Ferns (Presl*, 

 Meyenf), &c. In the Equisetaceje, Du Hamelf, Hedwig§, and 

 Vaucherjl regarded as stamens the extremities of the elaters, 

 upon which they had observed small granules ; Kolreuter re- 

 garded the shields of the spore-fruits as stamens ; — in the 

 Lycopodiacese the membrane of the capsules^. In the Rhi- 

 zocarpese^ most botanists regarded the small spores as male, 

 and the large as female organs**. 



Ferns (in the restricted sense). — Observations on the develop- 

 ment of Ferns from their spores led Nagelift to the discovery of 

 antheridia upon the lower face of the prothallium {pro-embryo 

 of some authors), preWously described (by KaulfussJJ, Nees v. 

 Esenbeck§§, &c.), and called the jjseudo-cotrjledon, Leszczyc- 

 Suminski, Wigand, Thuret, V. jMercklin, Schacht, Hofmeister, 

 and Henfrey have furnished contributions to the history of their 

 development and the knowledge of their contents. In their 

 origin and general structure they repeat the type of the antheridia 

 of jNIosses, and are usually elevated above the surface of the 

 prothallium upon one or a few superimposed peduncular cells. 

 Their envelope consists, according to Hofmeister|||], of a few 

 large cells. These enclose a globular group of small cubic cells, 

 whose walls are dissolved when the antheridia are ripe, and thus 

 set free the vesicles (primary nuclei of the cubic cells ?) con- 

 tained in them, which have the spiral threads in their interior. 

 The uppermost enveloping cell of the antheridia then tears in a 

 stellate manner, the spermatic vesicles escape, and are likewise 

 ruptured, letting out the spirally-wound spermatozoids, which 

 are furnished with numerous cilia at the anterior, thicker ex- 

 tremity. 



According to Wigand^^, the antheridia of diflFerent species, 

 and often even those of one and the same prothnllium, possess a 

 dififerent structure, in some cases consisting of a single cell. 



* Tentamen Pteridographiae. Prague, 1836, p. 15. pi. 11, a. b. 



t Pflanzenphysiologie, iii. p. 199. 



X Physique des Arbres. Paris, 1838. 



§ Op. supra cit. p. 35. 



II Monogr. des Preles. Mem. de la Soc. d'Hist. nat. de Geneve, i. pt. 2. 

 pp. 350, 359 (Geneva, 1822). 



H op. supra cit. pp. 119, 135; pp. 73, 1/4. 



** See the more complete bibliography in Mettenius, Beitr. z. Kenntn. 

 der Rliizocarpen. Frankfurt, 1846. 



tt Zeitschr. f. wiss. Botanik, i. Zurich, 1844, p. 168. 



XX Ct. Fr. Kaulfuss, Das Wesen der Farrenkrauter. Leipsic, 1827. 



§§ Entwickl. der Pteris serrulata. NovaAct. A.C.L.C. xii. pt. l.p. 157. 



nil Vergleich. Untersuch. Leipsic, 1839, p. 79 et seq. 



illF Alb. Wigand, Eutw. der Farrenki-auter. Bot. Zeit. 1849, p. 17; and 

 Botanisch. Untersuch. Brunswick, 1854, p. 44. 



