1 62 JOHN BELLING. 



The following notes may be of use. 



Canna. The pollen-mother cells are large and tender. The 

 anthers should be cut into segments about I mm. long, and 

 gently pressed out in a large drop of iron acetocarmine, being 

 left ten minutes or so to toughen before putting on the cover- 

 glass. (Here, of course, as usual, the anther remains are previ- 

 ously removed.) 



Zea. In maize the pollen-mother-cells are delicate, and the 

 same process is required as for Canna. 



Nicotiana.- In tobacco the pollen-mother-cells are easily 

 pressed out and stained. 



Datura. Resembles a small tobacco. Pollen hard to stain. 



Hyacinthus. Yields excellently stained pollen-mother-cells, 

 and also pollen-grains. The latter require several days to stain 

 well. Pressing out is difficult. 



Triticum and Secale. In wheat and rye all the pollen-mother- 

 cells are connected and come out of the anther loculus in a string. 

 The young anthers are cut across once, and pressed out under the 

 cover-glass. The pollen-grains stain well. 



Tradescantia. Stains deeply and shows chromomeres well in 

 pollen-mother-cells, and in pollen-grains. 



Uvularia. Shows chromosomes like those of the Orthoptera in 

 the pollen-mother-cells. Pollen stains well. Some metaphase 

 chromosomes of the reduction division show compound rings. 



llosta. Shows large and small chromosomes, the former with 

 marked chromomeres. Stains w r ell. 



Cypripedium acaule, and C. pubescens. Both pollen-mother- 

 cells and pollen-grains stain well. Ten pairs of chromosomes. 



Scilla sibirica. Pollen-mother-cells stain well. Shows six 

 pairs of chromosomes. 



Narcissus. Pollen-mother-cells and pollen-grains stain well. 



Galanthus. Pollen-mother-cells stain remarkably easily and 

 well. Several different sizes of chromosomes. 



The above plants have chromosomes which are especially 

 worth studying, because of their size and for other reasons. In 

 Brassica, Gladiolus, Iris versicolor, Asparagus, Dahlia, Capsella, 

 Hemerocallis, Antirrhinum, Stizolobium, Phaseolus and Crocus, 

 the chromosomes are either small, or clumped and not easily 

 unravelled. 



