AGB Glandular Hairs of Plants. [ May, 
cells overlapping each other. The lower cells are three or four 
times as long as broad, while towards the top the transverse 
diameter is the greater. The top of the 
projection is capped with a single hemi- 
aginous substance. All the other cells 
are in a greater or less degree transparent. — 
They are filled with a liquid containing 
granules which under a magnifying power 
AS) 
about in steady flowing currents. Some — 
but a single row of cells for the main por- 
| tion of their length. Perhaps still other 
Fic. $ FIG. 4. 
‘Fic. 3.— Slender hair of | 
Ageratum mexicanum. 
1c. 4.— Glandular hairs 
having two rows of cells. 
Fic. 7. 
Stout one-celled hair 
FIG. 5. Fic. 6. on Panicum capillare. 
Hair of Ageratum. Hair of Erigeron canadense. 
forms might be found which would be intermediate bewer 
some of these, showing more conclusively that they were modi- 
fied forms of the same members. 
Erigeron canadense, a common weed often known as horse-weed 
or mare’s tail, is clothed all over its surface with slender rapidly 
spherical cell which is filled with a mucil- 
of 250 diameters are often seen to move — 
_of these glandular hairs, like Fig. 5, have a 
