THE FEMALE GAMETOPHYTE 77 



burger 5 ), Trillium (Chamberlain 52 ), and Galtonia (Schnie- 

 wind-Thies' 95 ) four megaspores are reported, although in the 

 last genus only two may appear; in Anthericum (Strasbur- 

 ger 5 ), and Tricyrtis and Yucca (Guignard 12 ) three; in Alli- 

 um (Strasburger 5 ), and Agraphis and Ornithogalum (Guig- 

 nard 12 ) two; while in Lilium, Fritillaria, Furikia, Tulipa, 

 Convallaria (Wiegand 80 ), and Erythronium ( Schaffner 98 ) 

 the mother-cell does not divide. It may be of interest to note 

 the records of other investigators in reference to some of these 

 genera. For example, Ikeda 106 reports four megaspores in 

 Tricyrtis hirta, and Vesque 4 three in Hemerocallis, Allium, 

 .and Convallaria. 



Among the more primitive aquatic families, Zostera (Ro- 

 senberg 92 ) and Potamogeton (Wiegand, 66 Holferty 97 ) have 

 three or four megaspores ; in Typha ( Schaffner 49 ) there is no 

 division of the mother-cell; and among the Alismaceae, Alisma 

 (Schaffner 44 ) and Limnocharis (Hall 109 ) have an undividing 

 mother-cell, while Butomus (AYard 8 ) has three and sometimes 

 four megaspores. 



Among the Gramineae the complete tetrad is common 

 (Fischer 6 ), but Guignard 12 reports only two megaspores in 

 Cornucopiae. 



Among the Araceae Mottier 27 reports two megaspores in 

 Arisaema, and Campbell 75 the same number in Dieffenbachia, 

 while in the allied Lemna (Caldwell 62 ) the mother-cell does not 

 divide. 



Among the Pontederiaceae ( Smith 53 ) there are four mega- 

 spores, while Guignard 12 reports only two in Commelina. 



Among the higher families, Narcissus (Guignard 12 ) has 

 an undividing mother-cell; Iris (Guignard 12 ) has three mega- 

 spores (Vesque 4 reports four), and Tritonia and Sisyrinchium 

 (Strasburger 5 ) four; the Scitamineae have three or four, 

 excepting Costus (Humphrey 40 ), in which the mother-cell does 

 not divide; while the orchids Gymnadenia (Strasburger 5 ) and 

 Orchis (Vesque 4 ) have a row of three or four megaspores. 



That detailed study would show that many of these numbers 

 are not constant is indicated in several instances. In Arisaema, 

 in which two megaspores are customary, Mottier 27 found one 

 case in which the transverse wall did not form, the elongated 

 mother-cell appearing with a nucleus at each end ; while in Dief- 



