758 



LECTURE XLII. 



exterior ceases, as in the case of Fir- and Pine-cones, or so that even capsular 

 fruit-like bodies arise, as in Thuja and other Cupressmece. 



The case is quite otherwise with the flowering-plants. Here the ovules arise 

 from the beginning in the cavity of a special receptacle, which (with few exceptions) 

 completely excludes them from the atmosphere — a receptacle in which they will even 

 have to be sought out by the pollen-tubes subsequently. Accordingly the pollen- 

 grains cannot, as in the Gymnosperms, reach 

 the micropyle of the ovule directly, but are 

 conveyed on to a special part of the receptacle, 

 and thence send out their tubes to the ovules. 

 This receptacle bears the name of Ovary {Ger- 

 nien) : it is this particularly which distinguishes 

 the female reproductive apparatus of the flower- 

 ing-plants from that of the Gymnosperms. Since 

 the Greek word 'Ayyelov denotes a receptacle, 

 (in this case the ovary) it is customary to group 

 the flowering-plants — the Monocotyledons and 

 Dicotyledons under the name Angiospernis, and 

 thus contrast them with the Gymnosperms, or 

 naked-seeded plants. 



After these definitions, probably not entirely 

 superfluous for some of my readers, we may 

 now enter more in detail into those points which 

 alone really interest us here ; it is unne- 

 cessary for our purpose at present to regard 

 the two classes of Angiosperms separately. I 

 select therefore an example to hand, the flower 

 of one of our handsomest Monocotyledons, the 

 Flowering Rush {Butomiis timbellatus), for the 

 preliminary description of the reproductive 

 organs. In Fig. 441 A is represented a flower 

 in its natural size ; in B the floral envelopes 

 and the nine stamens are cut away, and the 

 whole female reproductive apparatus consisting 

 of six single separated carpels is represented 

 slightly magnified. Each carpel bears above 

 a narrow process, the so-called Style, which in 

 its turn bears at the upper end a brush of 

 hairs, the S/igma n ; this has the function of holding fast the pollen-grains 

 which have been carried to it from the opened anthers, in order that they may 

 germinate there, and put forth their pollen-tubes first in the tissue of the style 

 and then in the cavity of the ovary. 



It is easier in the case of Bidomus than in many other plants to perceive that the 

 carpel together with its style and stigma constitute practically a leaf with the margins 

 folded together longitudinally: this is obvious in Fig. 441 C, which represents 

 three carpels in transverse section. In other cases it is of course not so obvious, though 



KiG. 440. — P'ir-cone of Abies pcctinata (after 

 Schacht). A a leaf separated from tlie female floral 

 axis and looked at from above : it bears the ovuliferous 

 scale s with the ovules sk (magnified). B upper part 

 of the female flower (cone) m the mature state, j/axis 

 of the cone (floral axis) ; c its leaves ; s the much- 

 enlarged seminiferous scales. C a ripe seminiferous 

 scale s with the two seeds sa and their wings f 

 (reduced). 



