1922] JURICA—UMBELLIFERAE 295 
TREVIRANUS (70), and TANFANI (64). Quite recently an approach 
was made to the study of embryogeny by CAMMERLOHER (8), who 
studied the “Samenanlagen”’ of a large number of genera; and 
MarTEL (46) presented us with an anatomy of the flower. 
Summing up all the work done, however, we find that the 
Classification, gross morphology, anatomy, mechanical tissue, oil 
ducts, development of leaves and inflorescences, floral development, 
and development of fruit in this family are well covered, but 
embryogeny proper, endosperm formation, and the embryo still 
remain to be studied. It is with a view to filling this gap that this 
investigation has been entered upon. 
Methods 
The material used in this study was collected at different 
intervals in the vicinity of Lisle, Illinois. The fresh material was 
killed in a stock solution of chromo-acetic acid, imbedded in paraffin, 
and stained usually with either safranin and Delafield’s haemo- 
toxylin, or safranin, gentian violet, and orange G (omitted in a 
few cases). 
The study centers about Eryngium yuccifolium, with frequent 
comparisons with other genera, especially Sium cicutaefolium. 
Floral development 
No attempt has been made to present a study of the development 
of the inflorescence or umbel, for that has already been well studied 
by workers listed in the introduction. Nevertheless, since the 
umbels of Eryngium yuccifolium consists of distinct compact 
heads, a short note in regard to the head will not be out of place. 
The central or apical head of each umbel develops earlier and 
more rapidly than the encircling members, hence by the time the 
central head becomes visible to the naked eye, longitudinal sections 
show that the encircling heads develop in the axils of the bracts 
subtending the umbel, in much the same manner as described by 
Jurica (39) for the heads of Dipsacus sylvestris (fig. 1). 
As already has been described by JOCHMANN (38) for Eryngium 
planum, all the flowers in the heads of Eryngium yuccifolium arise 
from the axils of bracts spirally arranged. The blossoming begins 
