8o2 LECTURE XLVI. 



Ftinh'a ovafa and Allium /ragrans, two common garden plants, according to his 

 investigations, no embryo is developed from the actual oosphere in the embryo-sac, 

 not even when a pollen-tube may have happened to penetrate into the micropyle ; 

 but close to it cells of the nucellus of the ovule grow out into the embryo-sac 

 and embryos arise from these cell-proliferations. It is very probable that matters 

 are quite similar in the case of the Orange-tree also, and in the case of one of the 

 Euphorbiacese from Australia, Ccelehogyne, of which female specimens alone occur 

 with us. In all these plants several embryos are produced in the interior of the em- 

 bryo-sac by budding from the surrounding tissue. 



Among the phenomena of apogamy are also to be counted those cases in the 

 flowering- plants where, though flowers are developed, they are devoid of true 

 sexual organs, or where no flowers at all are developed. Here again the plants in 

 question are chiefly ciiltivated plants. Thus Müller designates certain Scitaminese 

 and Dioscoreae and also the Horse-radish {Armor acid) as entirely seedless, and De 

 Bary remarks in this connection that also our (of course not cultivated) Ficaria 

 and Dentaria bulbifera but rarely produce seeds ; among the species of the genus 

 Allium (Garlic) there are several in which small bulbils arise in place of the 

 flowers, and among these is also Allium sativum (the Garlic) in which no seeds 

 whatever are developed. 



The view that such apogamous species are undergoing extinction is opposed, 

 and correctly, by De Bary, with the remark that it is just among most apoga- 

 mous plants that an excessive production of asexually produced descendants tends 

 to occur. Sexual propagation is more than sufficiently replaced by asexual pro- 

 ductivity. 



