Meyen's Report for 1839 on Physiological Botany. 1/3 



M. Ilorkel* read a treatise in the Academy of Sciences of" 

 Berlin concerning tlie Polyembryony of the Conifera; ; his 

 own researches on this subject agreed perfectly uith those of 

 Robert Brown. In 1819 he had observed the small cavities 

 which appear in the end of the albumen oi Abies excelsa ; and 

 in the seed of Pi mis Cembra he observed, together with the 

 embryo, two abortive rudiments. In Abies excelsa M. Horkel 

 observed the rudiments of the ovula assume that form in 

 which Robert Brown has called them " Funiculi ;" they lay 

 in the middle of the great cavities of the albumen, parallel to 

 each other, generally three together, seldom four ; but M. 

 Schleiden has observed six rudiments in Pinus echinata. In 

 Taxus baccata M. H. never saw fewer than two rudiments, 

 but generally three ; but sometimes there is pnly one cavity in 

 the apex of the albumen. In the Cupressineae M. Horkel 

 always found only one cavity for the formation of the embryo, 

 lying in the axis of the albumen, but always two or four pollen- 

 tubes entered the cavity ; the Polyembryony of these plants 

 may therefore be ranked with that of Citrus ; it is, however, 

 not so accidental, but belongs more to their nature. 



M. Decaisnet has published some interesting researches on 

 the structure and fecundation of the ovulum of " Thesium," 

 which confirm the opinion I gave of Griffiths's description of 

 the structure of the seeds of Santalum album (former Report, 

 p. 33). A short time after fecundation has taken place a tube 

 (Schlauch) is seen to proceed out of the ovulum ; this tube 

 connects itself with another very fine one which descends 

 into the cavity of the ovulum from above. After the combi- 

 nation of these two has taken place, the tube swells and as- 

 sumes the form of a bladder, the lower part becomes filled 

 with cells. This tube is the embryo-sac, in the top part of 

 which the embryo is formed in shape of a small round bladder ; 

 and what is most remarkable is, that it is quite naked, and 

 therefore lies outside the nucleus (we have ah'eady shown that 

 this is also the case with Leguminosae, where however the 

 embryo-sac is enclosed in tunics (Eyhiillen, M.)) ; and that 

 the seed is also naked, only covered by the thin membrane 

 of the embryo-sac. During this formation of the embryo 

 one observes that a simple tube is formed, which is digitate 

 at the bottom and swollen at the apex ; the column pierces 

 this bag, in the centre of which it is enclosed, towards the 

 point of insertion of the impregnated ovulum, and places 



» Berichte iiber die Verhandlungen der Acadeniie der Wissenschafteu zu 

 Berlin, aus dem Jahre 1839, p. 92. 



t De I'ovule du Thesium.— Compt. Rend. 1839, No. G, p. 203. 



