A New Type of Transition from Stem to 
Root in the Vascular System of Seedlings. 
BY 
ETHEL SARGANT. 
With Plate XXXIII, 
OR some years I have been studying the comparative 
JL anatomy of Monocotyledonous seedlings, and I have 
paid particular attention to the transitional region in which 
the vascular system of the stem assumes the characters of 
a root-stele. This subject is the more interesting, as the 
anatomy of that region has as yet been described in few 
species of Monocotyledons. M. Gerard 1 describes it in 
nine Monocotyledons, and states expressly that his choice 
of material was limited because he was obliged to pick out 
species with comparatively long transitional regions. This 
is unavoidable when hand-sections only are prepared ; with 
the microtome very few seedlings are unmanageable. 
In the Wild Hyacinth (Scilia festalis, Salisb., Endymion 
or Agraphis of some authors), for instance, the transitional 
region is not only short but its symmetry is confused by 
the early formation of a vascular girdle from which the first 
cauline roots are given off. I have found it impossible to 
trace the behaviour of each stem-bundle during the transition 
with complete certainty in this species, although I have four 
perfect series of microtome sections cut through the critical 
regions of four well-grown seedlings at the right age. 
Such cases, however, are exceptional, and so are those 
1 Gerard, Recherches sur le passage de la racine a la tige. (Ann. des Sc. Nat., 
Bot., 6 e ser., t. xi, 1881.) 
[Annals of Botany, Vol. XIV. No. LVI. December, 1900.] 
