556 TRANS. ST. LOUIS ACAD. SCIENCE. 



shown in the figure. Following this layer are radially elongated 

 cells with thin walls. Next to the endosperm is a layer of cells 

 which resemble the thickened cross-bars or spiral bands found 

 in the aerial roots of many orchids like Oncidium^ Cattleya^ 

 Staiihopea oculata^ Dendrocolla teres^ Vajida furva.^^ They 

 likewise resemble the thickened bars found in the anther walls 

 of some Liliacece^ &c. 



Petalonta also is only represented by a single species in the 

 region of the Manual, — E, marginata, (See plate xii., fig. 11.) 

 The seeds are pitted and covered by a white substance which can 

 be removed very readily. The outer cells in a seed before ma- 

 turity are provided with thickened cross-bars. The palisade-like 

 layer is well developed, and provided with large pores as in many 

 of the species. These cells are twisted; they are largest at the 

 base. 



E. corollata^ of Tithynialofsis^ approaches E. ■polygonifolia^ 

 E. Geyeri, and others of that section. The seeds are shown on 

 plate xii., figure 12. The smooth seeds are ash-colored. The 

 white portion readily separates from the remainder of the seed, 

 so that frequently many of the seeds are of a brown color. This 

 part is also very brittle. A cross-section of the seed is shown on 

 plate xiii., fig. 12. The outer layer is mucilaginous, and the 

 cell-walls are greatly thickened and colorless. The cell-cavity 

 contains a dark substance. 



Cross-sections of the seeds were placed in alcohol ; stratifica- 

 tion could be seen, but on the addition of water these cells began 

 to elongate and the stratification was more pronounced. Iodine 

 produced no change in the walls of the mucilaginous cells, but 

 adding sulphuric acid caused the cell-walls to assume a violet 

 color, which changed to a bluish shade. The granular layer 

 beneath the mucilaginous cells is well developed. Iodine causes 

 the granules in these cells to become blue. Underneath the gra- 

 nular layer is a row of slightly elongated cells ; this is followed 

 by the palisade-like cells. The pores in these cells are not so 

 prominent as in the last species. The parts below the palisade 

 layer are usually much compressed. But two rows of cells can 

 be distinguished. 



52. G. HaberhuuU : Phj'siologische Pflanzenanatomie, Leipzig, 1SS4, Engelm., p. 159. 



