ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
423 
paper treats of morphology, including the following new points : — 
1. The transitory assimilating hairs during the period of elongation in 
early spring differ in several species examined, and further examination 
in other species may lead to the conclusion that difference in assimilat- 
ing hairs can be made to constitute a specific difference. 2. The 
primary axis of the assimilating hair is not regularly branched, but 
branches may occur singly or in pairs, and are separated by a varying 
number of axial cells. 3. At the end of the growing season the 
assimilating hairs are cut off by a definite method of abscission. 4. The 
cortical layer does not originate as filaments growing out from the basal 
cells of branch hairs which become applied to the axial cells, but as two 
groups of cells cut off from the basal cell of opposite paired branches,, 
which divide without definite order, and produce a single layer of cells 
covering the axial cell and the bases of its lateral branches, and so form 
a flat thallus. 5. There are two systems of secondary tissues : ( a ) the 
“ inner assimilation system ” and “ conducting hyphae ” which originate 
from the cells of the ground tissue ; ( b ) the secondary outgrowths 
from the lateral branches of the axial filament or 44 original thallus/’ 
which in very broad species form a network of veins in the lamina, 
visible from the surface. 6. The cells of the axial filament and all its 
branches, both primary and secondary, develop into true sieve tubes. 
A. a. 
Study of Susceptibility in some Puget Sound Algae. — C. M. 
Child ( Publ . Puget Sound Biol. Station , 1919, 2, 249-67). Experi- 
ments made on nearly a score of living marine algae with potassium 
cyanide, hydrochloric acid, ethyl alcohol, neutral red, potassium and 
sodium hydrates, methylene blue, and potassium permanganate. It was 
found that algae with apical growth exhibit a gradient in susceptibility 
which decreases down along the axis. In branching thalli also the 
highest susceptibility is at the apices. In Nereocystis it is at the regions 
of most rapid growth — the upper end of the stipes and the basal end of 
the frond. The pseudothallus of the diatom Navicula shows a distinct 
gradient of susceptibility corresponding with the growth-form, the 
apical region of each axis being most susceptible. With neutral red 
and methylene blue the early stages of staining follow a similar gradient, 
and in washing out a weak stain of methylene blue the action is 
quickest in the apical regions. Permeability alone will not explain the 
susceptibility ; a toxic substance either must alter the protoplasm in 
order to enter the cell, or else, passing through the protoplasm without 
killing it, produces its toxic effect by accumulating within the cell. 
A. Gr. 
Cape Cod in its Relation to the Marine Flora of New England. 
— William Albert Setchell ( Rhodora , 1922, 24, 1-11, 1 pi.). The 
importance of Cape Cod as a dividing point in the marine flora of the 
Atlantic coast of North America was first demonstrated by W. H. 
Harvey in 1852. The division between the northern and southern 
floras is however not sharp, as W. Gr. Farlow has shown ; some of the 
northern species are found in exposed localities south of Cape Cod, and 
some southern species in a few sheltered spots north of the Cape. 
Frank S. Collins accumulated most valuable data as to the algas along 
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