910] JEFFREY—PTEROPSIDA — 403 
of the higher plants in reference to the so-called apical meristems 
has long dominated morphology of a certain type, although its 
validity in relation to the histological structure of stems, roots, 
etc., has never been admitted by such distinguished anatomists 
as DEBARY and VAN TiecHem. It has not been any gain to 
anatomy that STRASBURGER, a morphologist of the reproductive 
structures and the cell, should have forced the growing-point 
hypothesis into the anatomical field in his one important contri- 
bution to vegetative histology. It is more unfortunate that his 
views have been adopted and elaborated by those who cultivate 
anatomy in England. With the overthrow of the hypothesis in 
regard to the morphological value of apical meristems, the views 
of the English anatomists, who have built on this uncertain founda- 
tion, have lost a fundamental support. That the application of 
the hypothesis of apical meristems to anatomical facts leads to 
hopeless contradictions and logical absurdities the present writer 
has shown in his article cited above. It appears to be unnecessary 
to repeat these arguments here. 
It must be admitted that the. English view, propounded by Dr. 
Scorr in a review of the present author’s investigations on the 
stele (Vew Phytol. 1902) and repeated with conviction by nearly 
all subsequent English writers on anatomical themes, has an air 
__ of probability in its favor, in spite of the fact that it can no longer 
summon to its support the hypothesis of the apical meristems. 
It seems prima facie improbable that the fibrovascular structures 
of the stem should be able to surround or contain tissues which 
é 
primitively lie outside. Moreover, the holders of the view in . 
 Tegard to the stelar origin of the pith have the advantage that 
_ their opponents in a measure face the logical impossibility of 
proving a negative. Although it is not possible to prove in all 
cases that the pith may be derived from outside the stele, it is 
fortunately only necessary to demonstrate this in a few instances, 
in order to invalidate the position of those who claim that the pith 
__ Is differentiated from the substance of the stele itself. 
Professor GwyNNE-VAUGHAN among English anatomists is the 
one who has shown the greatest openness of mind in regard to the 
_ $Srraspurcer, Ep., Bau u. Verrichtungen d. Leitungsbahnen. Hist. Beitr. 
: 3:1891 
