On Elaioplasts. 
BY 
RUDOLF BEER, B.Sc, F.L.S. 
With Plate IV. 
I N 1888 Wakker ( 1 ) described the occurrence of a conspicuous body lying 
in the epidermal cells of the leaves and in the superficial tissues of 
the root and stem of Vanilla planifolia . This body is somewhat larger 
than the nucleus and considerably larger than the amyloplasts ; it possesses 
a sharply-defined outline and a peculiar, somewhat yellowish colour. In 
each plate-like epidermal cell one such body occurs, and it often lies near 
the nucleus, although in other cases it may occupy a different position in the 
cell. As this body consists of protoplasmic material and contains oil, 
Wakker named it Elaioplast , or oil-former. 
He made a careful study of the effect of reagents upon the elaioplast, 
and briefly described the gradual disappearance of these bodies in older 
cells. Wakker was unable to study the origin of the elaioplasts as he had 
no suitable material for this purpose. He found elaioplasts also to occur in 
the cells of another species of Vanilla , known to him under the name of 
Vanilla aromatica latifolia. In 1893 Zimmermann ( 2 ) found similar bodies 
to occur in Funkia coerulia , F. lancifolia , F. Sieboldiana , Dracaena sp ., 
Ornithogalum scilloides , Agave americana , A. Mills , and in Oncidium 
suave. 
Raciborski ( 3 ) in the same year described elaioplasts in the tissues of 
various species of Ornithogalum , Albuca , Funkia , and Gagea. 
Zimmermann further found these bodies in the internal cells of the 
stem of P silo turn y and in the perianth leaves of Maxillaria picta. The shape 
of the elaioplasts differs in various plants, but it is usually constant in the 
same species. Spherical forms, grape-like bodies, irregular plasmodium-like 
masses, have all been described. 
Usually only one elaioplast occurs in a cell, but in some cases they may 
be more numerous (e. g. Ornithogalum). The finer structure of the elaio- 
plast has been carefully examined both by Zimmermann and by Raciborski. 
It has a finely granular appearance due to the occurrence of a number of 
tiny, highly refractive spherical bodies lying in its substance. One or more 
less refractive spots often occur within the elaioplast. The elaioplasts of 
[Annals of Botany, Vol. XXIII. No. LXXXIX. January, 1909.] 
