20-1 Br. L. Kadikofer on true Purthenoyenesis in Plants. 



XXII. — On true Parthenogenesis in Plants. 

 By Dr. L. Radlkofer, of Munich*. 



It would indeed be difficult to find anywhere a more evident 

 proof of the imperfection of human knowledge than is furnished 

 by the contradictory results of the latest embryological investi- 

 gation, in the departments of zoology as well as of botany. If 

 our knowledge of the process of fecundation in animals appear 

 to have made an important step forward through the observation 

 of the penetration of the spermatozoids into the ovum, — if this 

 seemed to put beyond all doubt the material participation of the 

 spermatozoids in the formation of the embryo, — we nmst be 

 doubly surprised by the observation, that in particular — appa- 

 rently determinate — cases, the formation of the embryo occurs 

 without any cooperation of the spermatozoids, therefore without 

 previous fecundation of the ovum. This true Parthenogenesis, 

 demonstrated with all the exactness which science can require 

 by Prof. Von Sieboldf, in the Lepidoptera, and in the Eees 

 particularly, is paralleled by analogous cases in the neighbouring 

 domain of plants. 



In calling the attention of zoologists for a moment to an 

 account of them, I have a twofc^ld purpose : to convince those 

 still in doubt by the number of proofs, and to attract to the 

 subject itself as many observers as possible. 



Embryological researches in the vegetable kingdom have kept 

 pace with those in the department of zoology. Analogues of 

 the animal ovum, analogues of the animal fecundating matter, 

 have been demonstrated in all groups of the vegetable kingdom, 

 with the exception of the Fungi and Lichens. 



To the ovum corresponds the germ-vesicle of the Phanero- 

 gamia, of the Khizocarpese, Equiseiacea^, Ferns and Mosses; 

 and, besides this, the primordial spore- cell of the Alg;je. The 

 germ-vesicle {vegetable ovum) presents itself as a perfect cell, 

 furnished with a membrane and a cytoblastj:; in the Algse we 

 find, instead of the perfect cell, one devoid of a membrane, an 

 ovum without an integument, — the naked primordial spore-cell. 



To the spermatozoids contained in the spermatic Huid of ani- 

 mals, the material basis of which we must regard, according to 



* Translated from Siebold ami Kolliker's Zeitselirift, viii. Heft 4(1857j, 

 by Arthur Henfrey, F.R.S. &c. 



t True Parthenogenesis in Moths and Bees, &e. By C. Th. You Siebold. 

 Translated by AV. S. Dallas, F.L.S. London, Van Voorst, 1857. 



X We dissent from the author on this point, believing that the luiim- 

 pregnated germ-eell has not yet a cellulose membrane, but resembles the 

 unim{)regnated s])ore of Fucus. See Annals of Nat. Ilist. l.'ud scr. xviii. 

 p. -'17 (Sept. ie5<;).— [A. II.] 



