JANUARY 26, 1912) 
Moisture equivalent 
1.84 (1+ 0.007) — 
Hygroseopic coefficient 
0.68 (1+ 0.018) 
Wilting coefficient = 
Wilting coefficient = 
Wilting coefficient = 
Moisture-holding capacity — 21 
2.90 (1 + 0.021) 
Wilting coefficient = 
0.01 sand + 0.12 silt + 0.57 clay 
(1 + 0.025) 
Inhibiting Factors in Lychnis and Papaver: 
GEORGE HARRISON SHULL, Carnegie Institution. 
A cross between -white-flowered and purple- 
flowered forms of Lychnis dioica L. (Melandrium 
-album and M. rubrum), both from Germany, have 
given an F, predominantly white-flowered, though 
numerous previous crosses between other white- 
-flowered and purple-flowered strains of this species 
have invariably produced only purple-flowered off- 
spring in the F, The white-flowered form from 
Germany, in crosses with a ‘‘recessive white’’ 
American strain, produced in one ease a white- 
flowered F,, in another case a purple-flowered F,. 
In Papaver Rheas white has usually proved to be 
recessive to colors, but in one instance a cross 
between deep red and white produced a completely 
whitish progeny in the F,, and the same result was 
also attained in a cross between two deep red 
parents.. The latter experience suggests the ex- 
istence of two complementary inhibiting factors, 
A and B, which have no effect except when co- 
existing in the same plant. 
Inheritance in Capsella: H. Hus, University of 
Michigan. 
Seedlings from a single plant of Capsella Bursa- 
pastoris can be classed in three groups: broad- 
leaved, narrow-leaved and linear-leaved. These 
forms occur approximately in the proportion 2:2:1. 
This proportion, which has been maintained for 
three generations, may perhaps be looked upon as 
a simple Mendelian splitting in the F, generation, 
of the Zea type, complicated by a defective in- 
heritance ratio. This contention meets with the 
objection that the linear-leaved form represents a 
type thus far unreported. 
The Origin of the Erect Cells in the Phloem of 
Abietinee: M. A. CHRYSLER, University of 
Maine. 
If a medullary ray in such a genus as Pinus is 
traced outward from xylem to phloem, it is well 
known that the marginal tracheids of the woody 
part of the ray may be seen to be replaced in the 
SCIENCE 
159 
phloem by nucleated cells which are somewhat 
elongated in the longitudinal direction, the so- 
called ‘‘erect cells’’ of the ray. From a study of 
the roots of seedlings it is found that various 
transitions between these erect cells and sieve- 
tubes occur. Groups of elongated cells provided 
with nuclei and sieve-plates are a common feature 
of the phloem of these young roots, and where such 
a group meets a medullary ray certain of the 
elongated cells become applied to the ray and 
become progressively shorter, forming the erect 
marginal cells, while the rest of the elongated cells 
give place to ordinary sieve-tubes. Thus from 
what may be called primitive sieve-cells the sieve- 
tubes are derived by elongation, and the erect 
cells of the ray by shortening. 
Do the Abietinee extend to the Carboniferous? 
R. B. THomson and A. E. ALLIN, Toronto Uni- 
versity. 
The claims for the great geological age of the 
Abietines (see Jeffrey and Chrysler, Bot. Gaz., 
p. 13, 1906) are based on the occurrence of 
Pityoxylon chasense in the Permian and on the 
supposed occurrence of P. Conwentzianum in the 
Carboniferous. 
P. chasense was described by Penhallow in 1900. 
The pitting of the tracheids is of the Araucarian 
or Cordaitean type (1-3 seriate, alternate and 
hexagonal) and bears not the slightest resem- 
blance to that of Pityoxylon as defined by Kraus 
(one-seriate, or opposite when two-seriate), or to 
that of an Abietinean form. Penhallow, however, 
placed this form in the genus Pityorylon because 
of the occurrence of what he supposed were hori- 
zontal resin canals. A careful study of the type 
material has revealed that they are not resin 
canals but leaf traces quite comparable to those 
in certain Cordaitee and Araucarinee. This Per- 
mian Pityoxylon is, therefore, a true Cordaitean 
or Araucarian. 
Gothan has recently shown that P. Conwentzi- 
anum, which is commonly attributed to the Car- 
boniferous but whose horizon was never deter- 
mined, can not be an authentic Carboniferous 
form. 
The geological claim for the great antiquity of 
the Abietiner thus fails on critical study of the 
two forms upon which it is based. 
Ingrowing Sprouts of Solanum tuberosum: C. 
Stuart GaGER, Brooklyn Botanie Garden. 
The paper described a case in which the sprouts 
of a large number of potatoes grew into and 
through the tubers that bore them, ramifying 
