107 



Since it is hardly possible in a short review to present in 

 detail the results of this throughgoing study, I shall summarize 

 only what are apparently the most important conclusions. 



In all of the plants studied except Houstonia two ovules and 

 one integument are present ; Hoiistonia has many ovules and no 

 integument, realizing the " nucellus nudus " of Schleiden. In 

 the Spermacoceae, there is, in addition to the integument, an out- 

 growth which contains the vascular supply of the ovules and 

 is the seat of a large number of excretory cells. This is termed 

 the strophiole. 



The archesporium, except in the Spermacoceae and Olden- 

 landeae, contains 7—15 macrospore mother-cells, and each macro- 

 spore mother-cell divides twice to form four spores, which are 

 physiologically and morphologically equivalent, and any or all of 

 which may undergo one division although the functional embryo- 

 sac is derived from the middlemost of the group. In the 

 Spermacoceae and Oldenlandeae there is but one macrospore 

 mother-cell. 



The embryo-sac presents some curious and interesting devia- 

 tions from the usual conditions that obtain in the higher plants. 

 The embryo-sac either develops where the macrospore is formed 

 {Houstonia and Richardsonia), or it moves along the micropylar 

 canal, and in extreme cases (as in Asperuld) the mature embryo- 

 sac may partly protrude from the end of the canal and come to 

 lie between the integument and the pericarp. 



As regards the antipodals, although invariably present, they 

 vary greatly both as to function and number. Perhaps the most 

 interesting of the antipodals described are those of Callipeltis 

 Cucullaria, of which one is greatly elongated and acts as a 

 haustorium, by the action of which the supernumerary macro- 

 spores are destroyed and their contents ingested and made avail- 

 able as food for the developing embryo-sac. 



The young embryos of the Galieae are provided with haustorial 

 outgrowths that project laterally from the suspensor. Their 

 function as absorbers ceases as soon as the adjacent endosperm 

 cells become filled with reserve food, and their walls become 

 thickened to form a reserve cellulose. 



