70 



T. Holm — Erigema hidbosa. 



liarity as seems characteristic of the TTmbelliferce in general, 

 i. e., the mestome-bundles are separated from each other, and 

 in this genus they are arranged in the form of an arch ; there 

 is no collenchyma ; ducts with four special cells occur in the 

 leptome besides that a larger duct with six special cells is to be 

 observed beneath each of the three mestome-bundles on the 

 leptome side. The leaf-blade of the cotyledon shows a bifacial 

 structure with stomata on both faces, most numerous on the 

 lower surface; a palisade-tissue of one 

 stratum occupies the upper part of the 

 blade, while an open pneumatic tissue 

 occupies the lower. Large ducts with six 

 special cells are visible above and below 

 the mestome-bundles, but neither the 

 smaller ducts, rhombic in transverse sec- 



Fig. 6. Transverse 

 section of a part of a 

 mestome-bundle of the 

 cotyledonar petiole of 

 Erigenia. Two ducts (D) 

 one with four, the other 

 with six special cells. 

 x400. 



tion, or collenchyma were found at this 

 stage. In the petiole of a large leaf taken 

 from a flowering specimen, there are five 

 isolated mestome bundles forming an arch 

 as in the cotyledon, and we noticed eleven 

 oil-ducts, all of which were large and sur- 

 rounded by five or seven special cells ; 

 these ducts are located in the cortical 

 parenchyma, and mostly separated from 

 the epidermis by a small group of collen- 

 chyma. The blade of the mature leaf has 

 stomata only on the lower surface, and the 

 cells of epidermis on the upper face are 

 extended into minute, roundish papillae, which along the 

 margin attain the shape of pointed, thick-walled prickle-like 

 projections. Otherwise the structure is like that of the coty- 

 ledon, and oil-ducts, were, also, found here above and below 

 the mestome-bundles. 



The stem above ground is obtusely triangular in transverse 

 section and shows a rather weak structure with only moderately 

 thick-walled collenchyma in small groups, inside of which we 

 noticed the usual large ducts as in the petiole. But we found, 

 also, the smaller ducts, and these occurred in the leptome, one 

 on each side of this. Five mestome bundles surround a thin- 

 walled pith, of which the innermost portion is broken down, 

 leaving a wide cavity in the middle of the internode. While 

 oil-ducts are known to occur in the pith of several genera of 

 this order, it seems as if they were lacking in Erigenia; we 

 were, at least, unable to find any of these ducts in the pith in 

 spite of very careful research. 



The peduncle of the umbel is quadrangular in outline and 

 the angles are rough from the presence of small prickle-like 



