1893.] The Roots of Ranunculacee. 13 
Here Erickson includes most of the Leguminose and a few 
species from several other groups, including all of the Ranun- 
culacee which he examined, though saying that these differ- 
ed from the type in that the periblem developed centrifugally 
instead of centripetally. 
Fourth type, roots having but two well marked meristem 
tissues, a plerome and a periblem, the outer layers of the cor- 
tex answering to the epidermis and root-cap. This agrees 
with Janczewski’s fifth type which he made for gymnosperms. 
In an article published in 1878?° Flahault discusses the 
theories of structure of the root at its vegetative tip. He 
thinks that it was on account of Hanstein and Reinke not 
understanding the early separation of the calyptrogen from 
the dermatogen that they placed monocotyledons in the Heli- 
anthus type. After making a study of the roots of three 
hundred and fifty species, representing nearly all of the natural 
orders of plants, he makes two types of primary. meristem for 
angiosperms, one for dicotyledons and one for monocotyle- 
dons, distinguishing the two types by the latter always hav- 
ing a distinct calyptrogen layer. The other types as made 
out by Janczewski and others he would regard as but forms of 
these two, for between them are all manner of gradations, 
while the two main types are very distinct. 
Fleischer?! found that in a ¥ancus and Luzula the root-cap 
had an origin of its own while other plants he studied con- 
formed to the Helianthus type. Bruchman claimed to have 
made out four primary meristem tissues in the roots of grasses 
which he studied, but did not give details of work or results. 
hus we see that later workers agree that Hanstein and 
Reinke’s assumption of one type of meristem structure for all 
phanerogams was untenable. As to how many types there 
are opinions differ widely. 
M. Halle?? tried to reduce Janczewski’s two types for 
dicotyledons to one type, and adds a number of species as 
belonging to the Helianthus type. He considered Janczew- 
ski’s fourth type the result of degeneration through excessive 
development at the vegetative point. He made careful studies 
of the embryos of many Leguminose@, said to belong to this 
20Recherches sur l'accroissement terminal de la racine chez les phanero- 
gams. Ann. des Sci. Nat. VI. vi. 
21 Beitraege zur Embryogenie der Monokotylen und Dikotylen. Flora, 1874. 
2? Bot. Zeit. 1876 and 1877. 
