SMITH: THE HISTOLOGY OF CERTAIN ORCHIDS 9 
Mucilage cells in mature flower Bundles of raphides in corresponding 
cell 
Width Length Width Length 
241 19 74 
37 259 19 74 
26 204 15 74 
37 296 15 74 
Such a cell contains a large bundle of crystals imbedded in a 
homogeneous mass of mucilage stained yellow by the orange of 
the triple stain. Between the mucilage and the cell wall there 
is a layer of cytoplasm in which the large nucleus with a con- 
spicuous nucleole and chromatin is imbedded. In face view the 
nucleus is oval in outline and in profile view it is seen to be some- 
what flattened against the cell wall. These nuclei appear quite 
normal. Thechromatin takes the blue and thenucleole the red in 
the triple stain. The appearance of the nucleus in the mucilage 
cells of Aspasia sp. is very different from that described by Miss 
Stewart, Lloyd and Walliczek for the nucleus in the cactus slime 
cells. In the matureslime cell of the A spasia i it still has the aspect 
of an actively functioning organ; in the cactus the descrip- 
tions show that it is degenerating and lacking the normal differen- 
tiation into nucleole, chromatin, nuclear membrane, etc. There 
was no indication in the mature flower of any change in the char- - 
acter of the secretion in the mucilage cells. No chloroplasts or 
starch were observed in the slime cells. The only inclusions seen 
were small oval bodies which stained a bright red like the enve- 
lopes and strands of the bundles of raphides. In Aspasia sp. 
raphides and slime were always found associated and neither 
was found in a mature cell without the other. The crystals 
dissolved in hydrochloric acid without forming bubbles, showing 
that they are calcium oxalate. They were not observed in 
epidermal cells, and there was no evidence of their disappearance 
in the open flower stage. The sac about the bundle of raphides 
in no case observed took the same stain as the surrounding 
mucilage. 
ONCIDIUM STIPITATUM 
Abundant production of raphides imbedded in mucilage was 
observed in this species. The red staining sheath about the 
bundles was not as conspicuous as in the cells of Aspasia sp. 
