elimination of autogamy. Special growth-curvatures and movements may be effected 

 during the period of floral presentation. 



The Ovule : Typically small and much like the egg of insects, as flies and moths, 

 hence name ; strictly a megasporangium producing one megaspore, as the limiting 

 case. Originating as a massive emergence of the carpellary margin, or ' plac< 

 (nucellus), on a stalk-portion (funicU), not always expressed ; and invested by 2 (or i) 

 collar-growths (in/fgvmfn/s) t outer and inner, closing over the apex of the nucellus 

 leaving only a narrow pore (microfyU). 



The body of the ovule is commonly bent on the stalk (raphe) in anatropous 

 fashion ; bent on itself (campylotropous) or more rarely orthotropous. Nutrition is 

 effected by one V.B. terminating in the chalazal- region. Within the nucellus one 

 large megaspore is differentiated ; stages of archesporium, tetrads, tapetum, etc., are 

 abbreviated as vestigial relics, but meiosis occurs, and the surviving spore is one of 

 a tetrad : it is commonly known as ' embryo-sac ' (megaspore). 



The special point is that this spore is not shed but germinates in situ directly, 

 the ' spore-stage ' being imperceptible : this expresses the state of the Phanerogam or 

 Seed-riant, as the necessity for a dispersal-stage (seed) follows at some later date 

 from such failure of the original mechanism of spore-discharge. 



Noli the function of the carpel is to produce ovules each with one megaspore : 

 that of the stamens to produce pollen-grains : the latter, in pollination, are brought 

 as near as possible to the vicinity of the megaspores, that they may germinate and 

 grow to new individuals, side by side : Both types of spore give rise to minute holo- 

 parasitic structures as the sexual phases of the organism. 



NARCISSUS poe/icus affords a convenient type, the female prothallus being 

 ready for fertilization when the flowers are at their best. In many types with large 

 ovaries (Li/ium, Tulipa, Iris) this does not obtain. 



Gynoecium, syncarpous, of 3 carpels, ovary inferior, placentation axile ; ovules 

 numerous and fairly transversely extended in the loculi. The flower is horizontally 

 projected, with white star-perianth, target-eye, powerful scent, and narrow tube 

 (30 mm.) to honey-supply from septal-glands of ovary opening at base of style, as 

 a highly specialized Moth-mechanism. 



Transv. sect, of ovary, material fixed in abs. ale., gives good results : 



Note : large ovules, oval, i mm. broad ; micropyle, integuments, the outer one 

 fused with raphe along one side ; V.B. prominent in raphe, and defining the chalazal 

 region. Embryo-sac \ as large oval cavity, empty, or with scanty contents, 450500 ^ long. 



Contents of Embryo sac, not necessarily seen in same section, as a few large 

 nuclei, and strands or portions of network of plasmatic bridles. 



(1) Micropylar group of three nuclei ; as oosphere, 50 /x diam., a large nucleus 

 with film of cytoplasm only: two smaller synergidae, 20 p. nuclei, with slight cytoplasm. 



(2) Central fusion-nucleus, large 60 p. diam., spherical, aqueous, with con- 

 spicuous nucleolus ; often out of position, and resting on antipodal group. 



(3) Antipodal group of 3 nuclei, 30/1 or more, with nucleoli, surrounded by 

 vaculolated cytoplasm and thin cell-walls ; in a close cluster. 



The whole constitutes the female prothallus as a distinct individual organism, 

 in no protoplasmic continuity with the nucellus, and wholly parasitic on it, as 

 a minimum organization, the culmination of a long line of descent from a prothallus 

 bearing archegonia in the manner of a Fern-prolhallus, and beyond this from a 

 free-living algal organism of aquatic submerged habit. As types of gynoecium cf. : 



Wallflower: Tetramerous, actinomorphic; Gynoecium based on 2 carpels; ovary 

 syncarpous, superior, 2-locular, with parietal placentation and numerous ovules : stigma 

 2-lobed, commissural. 



Viola : Pentamerous, zygomorphic ; Gynoecium based on 3 carpels ; ovary syn- 

 carpous, superior, unilocular, with parietal placentation, numerous ovules. Style bent, 

 stigma papillose, not lobed. 



Clematis : Tetramerous (5-6), actinomorphic, coloured perianth only ; Gynoecium 

 apocarpous of indefinite carpels, each with one anatropous suspended ovule and 

 rudiments of others. 



Snapdragon : Zygomorphic, gamopetalous, 2 : 3 -lipped corolla : Gynoecium 

 based on 2 carpels; ovary syncarpous, 2-locular, with axile placentation, indefinite 

 ovules; stigma bilobed. 



8 



