THE MALE GAMETOPHYTE 



125 



microspores lying side by side, and measuring 3 by 2,000 p 

 when mature. That this is a tetrad is evident from the rapid 

 succession of the divisions, the reduction of chromosomes, and 

 the formation of four spores from a mother-cell. 



In some cases a mother-cell may give rise to less than four 

 microspores, or may produce more than the normal number 

 (Fig. 60). In 1886 Wille 15 summarized the work of previous 

 investigators, notably of Hofmeister, Tangl, Wimmel, and 

 Tschistiakoff, and added the results of his own investigations. 

 The following lists are made 

 up largely of forms investi- 

 gated by Wille himself: 



Two microspores from 

 a mother-cell are occasion- 

 ally found in Convallaria 

 multiflora, Asparagus offi- 

 cinalis, Aconitum Napellus, 

 Euphorbia Lathyrus, Be- 

 gonia sp., Saxifraga caespi- 

 tosa, Azalea indica, and 

 Syringa vulgaris. 



Three microspores were 

 found in Begonia sp., Sa.i't- 

 fraga caespitosa, Azalea in- 

 dica ', and Lonicera coerulea. 



Five microspores were 

 found in Funkia ovata, Fi- 

 ta ria ra n u n c u lo ides, Ste l- 

 /c / ia qla u ca, Scleran tli us 

 annuus, Primus Cerasus, 

 Eumex Patientia, Azalea 

 indica, Lonicera coerulea, 

 Syringa persica, and Sym- 

 pliylum officinal e. 



Six microspores were found in Hemerocallis fulva, Ficaria 

 ranunculoides, Elaline hexandra, Cornus sanguinea, Lonicera 

 coerulea, and Fuchsia sp. 



Seven microspores were counted with certainty in Fuchsia 

 sp. and fourteen are reported rather doubtfully; eight is given 

 for Azalea indica, and eight to twelve for Lonicera coerulea, 



FIG. 56. Scrophularia nodosa. Section of mi- 

 crosporangium showing appearance of spores 

 formed by the simultaneous method; the 

 inner tapetum of microsporangium consists 

 of greatly elongated cells which are very 

 glandular in appearance, x 275. 



