144 BOTANICAL GAZETTE [august 



Two megaspore mother cells 



Among the monocotyledonous plants, 2 megaspore mother cells 

 in the same nucellus have been reported in but few instances. In 

 Ornithogalum pyrenacium, Guignard (15) reports that 2 large cells 

 ("deux grosses cellules collaterales") are often present at the apex 

 of the nucellus. Bernard (i) has reported 2 embryo sacs in Lilium 

 candidnm in the same nucellus. Coulter and Chamberlain (ii) 

 report two cases in Lilium philadelphicum, in one of which 3 

 " archesporial cells " were present in the same nucellus and in the 

 other 5. Miss Ferguson (14) has called attention to a single case 

 of the occurrence of 2 mother cells separated by a layer of somatic 

 cells in a single megasporangium of Lilium longiflorum. Lechmere 

 has also reported (16) for Fritillaria messanensis 2 embryo sacs which 

 apparently have arisen from distinct mother cells side by side in a 

 single ovule. 



In the genus Smilacina 2 megaspore mother cells or their deriva- 

 tives occur occasionally in the same nucellus. In S. stellata I have 

 observed in four different cases 2 partially developed embryo sacs 

 in the same nucellus, separated by somatic tissue (fig. 10). There 

 can be no doubt that these have arisen from distinct mother cells. 

 In 5. sessifolia 2 mother cells were frequent. On one raceme, 

 approximately one nucellus out of 4 contained either 2 mother cells 

 or 2 developing embryo sacs. As is shown in fig. 9, they are usually 



or les^ hv somatir rplls Tn £. racp.mosa 2 mother 



more 



cells or embryo sacs were in several cases observed lying side by side 



some 



others separated by sterile cells. In S. amplexicaulis 2 mother cells 

 in the same ovule were observed on several occasions. While a 

 complete record was not kept of all preparations showing this, I have 

 records of five such abnormalities. As is shown in fig. 12, they are 

 usually separated more or less by somatic cells. 



In Polygonatum cornmiitaium 2 mother cells in one megaspo- 

 rangium were occasionally observed (fig. 45). Four such cases have 

 been recorded but others were observed. In Maianthemum cana- 

 dense three cases were also observed of 2 megaspore mother cells 

 in the same nucellus. As will be seen from fig. 17, the nucellus is 

 abnormally broad and the mother cells arc partially separated by 

 disintegrating somatic cells. 



