70 
Beer, ~0n Elaioplasts . 
Summary. 
1. Elaioplasts which hitherto had only been met with in Monocotyledons 
(and Psilotum ) have now been found to occur in a Dicotyledon — Gaillardia. 
2 . The elaioplasts occurring in the corolla-hairs of Gaillardia are 
found to agree in their appearance and in their reactions with the elaio- 
plasts described by Wakker and Zimmermann in Monocotyledons. 
3. They have been found in the corolla-hairs, the pappus, the connective 
of the stamens, the style and the stigma of Gaillardia. They are absent 
from the tissues of the stem, the root, and the leaf of this plant. 
4. They are formed by the aggregation of plastids and their degenera- 
tion products at one or more spots in the cell. 
5. In the corolla-hairs of Gaillardia they give rise to the oily, yellow 
pigment which, in association with the red cell-sap, gives the mature hairs 
of the flower their characteristic colour. 
6 . The elaioplasts occurring in the stamens and in the style and stigma 
of Gaillardia agree in all respects with those of the corolla-hairs except 
that they are coloured green with chlorophyll, and can form starch within 
their substance. In neighbouring cells of these tissues all transitions occur 
between elaioplasts, which are coloured brightly green, and those which are 
almost colourless like those of the corolla-hairs. 
7. In the tissues of the young pappus every transition can be found in 
neighbouring cells between those which contain scattered chloroplasts 
entirely free from one another, and those in which the chloroplasts have 
clumped together to form a green mass identical with the green elaioplast 
of the stamen or the stigma. 
8. The elaioplasts of Gaillardia (and probably of the Monocotyledons 
also) differ essentially in their development from the oil-bodies of the 
liverworts. 
9. External conditions were found to exert very little influence upon 
the appearance of the elaioplast, although rather strong, direct illumination 
seemed in one case to have somewhat retarded the aggregation of the plastids. 
10. The close massing of the plastids into compact elaioplasts is 
probably connected with their degeneration, and may be compared to the 
aggregation of the plastids under the influence of various (mostly injurious) 
agencies described by several previous writers. 
11. It is most unlikely that the elaioplasts perform any function of 
direct importance to the life of the plant, although they may in some cases 
(corolla-hairs of Gaillardia) serve a secondary, biological purpose. 
