1898-99.] MORPHOLOGY OF THE CENTRAL CYLINDER IN THE ANGIOSPERMS. 615 
tissues should in some species of a given genus be intrastelar and in 
other species extrastelar. He accordingly regards the phlceoterma 
which surrounds the whole complex of bundles in the so-called mono- 
stelic type as morphologically different from the individual sheaths 
enclosing the bundles in Van Tieghem’s astelic type. Strasburger has 
apparently overlooked the fact that Van Tieghem® had anticipated his 
objection to the different morphological interpretation of the pith in 
different species of the same genus, by announcing that in the case of 
the cryptogamous orders, the Equisetacee and Ophioglossacee, the 
medullary tissue is always extrastelar, thus, as has already been pointed 
out, departing from the view originally expressed in his essay on 
Polystely. Van Tieghem® still maintains, however, his earlier position 
in regard to the varying morphology of the central cylinder in different 
species of Ranunculus and Anemone. 
We now come to the consideration of the development and structure 
of so-called astelic axis in the Ranunculacee and other groups. 
RANUNCULACE As. 
Our knowledge of the anatomy of this order is chiefly due to the 
studies of Marié.” Although he has described quite exhaustively the 
salient structural features of the root, stem, and leaves of this order, he 
has given little or no attention to the subject of the development of the 
stem, which, as the writer hopes to show, is of considerable importance 
from a morphological standpoint. Quite recently Jancezewski® has 
examined the anatomy of a number of species of Anemone. Stras- 
burger” attributes to Marié the statement that Ranunculus acris pos- 
sesses a common endodermis (phlceoterma), z.2., in other words, that the 
central cylinder of this species is medullated monostelic. Marié’s 
description” is extremely condensed, and, on that account, is some- 
what ambiguous; but the writer is inclined to interpret it as mean- 
ing that the bundles of this species have individual endodermal sheaths, 
since he states that XR. acres resembles R. multifidus, which has individual. 
endodermal sheaths. 
35- Journ. de Bot., 1890. 
36. Elements de Botanique, p. 179. 
37. Récherches sur la Structure des Rénonculacées. Ann. de sci, Nat. Bot., 6 sér., tom. 20. 
38. Révue Générale de Botanique., 1898. Etudes Morphol. sur le Genre Anemone. 
39. Op. Cit., p. 311. 
40. Op. Cit., p. 80, 
