STAMEN AND POLLEN OF HEMEBOCALLIS. 381 



cultivated white or tiger Lilies, Tulip, Crown Imperial, etc., 

 will do equally well. The yellow filament is here very long, 

 becomes thinner towards its upper end, and tapers very sharply at 

 the place of insertion of the anther. This latter is brown in 

 Hemerocallis, and movable (versatile or centrifixed) upon the 

 filament. The connective can be traced along the outer side 

 of the anther as a thin stripe between the two anther-lobes. 



The Pollen-Grain. The ripe pollen, observed dry upon the 

 object-slide, shows the form of coffee berries, the general form 

 in Liliacese. It appears yellow, ornamented with a network of 

 ridges on its surface. If, while examining, we allow water to 

 enter from the edge of the cover-glass, we see that each pollen- 

 grain, as soon as wetted, levels up its furrow, strongly bulges out 

 on this particular side, and takes the form of a unilaterally^ 

 flattened ellipsoid. The membrane of the previously-furrowed 

 part is without ridges, is thick and colourless, and is delimited 

 sharply against the sculptured, brownish membrane. This brown 

 membrane is the outer wall of the pollen-grain, the exine (or 

 exospore) ; the swollen colourless membrane is the inner, the 

 inline (or endospore). In the swelling of the pollen-grain the 

 exine has been ruptured in the grooved side, and the strongly- 

 thickened intine protrudes. On the opposite side the intine is 

 present only in the form of a delicate skin. The exine sub- 

 serves the protection of the pollen-grain, and completely covers 

 it in its normal furrowed condition. Between the pollen-grains 

 in the preparation orange-red oil is distributed, and it clings 

 also to the surface of the grains, giving to them in the dry 

 state their yellow colour. The contents of the pollen- grain ap- 

 pear grey and finely granular. After a short time, during which 

 the pollen-grain slowly and progressively enlarges, it bursts and 

 empties its contents, in worm -like form, into the . surrounding 

 water. In sugar solution of suitable concentration the grains, 

 round off without bursting, and can be examined uninjured. 



If we allow concentrated sulphuric acid to act upon the pollen- 

 grains, the colourless smooth part of their wall is at once dis- 

 solved, while the sculptured, brownish part, on the other hand, 

 resists : it is cuticularised. If into a preparation of pollen-grains 

 in water we run watery solution of methylene blue, the cuti- 

 cularised exine assumes a faint greenish- blue colour, the swollen 

 intine bright blue, somewhat shading into violet. If instead of 

 methylene blue we use watery safranin solution, the exine is. 



