64 
character is IRGOgp. Taking into consideration only cotyledon 
color and texture, this type when crossed with all ordinary green 
cotyledon types gives an F2 9: 3:3: 1 ratio. Crossed with the 
P30 type (irg) an F, ratio of 13 yellow : 3 green is obtained, with 
complications respecting the R factor as described above. Over 
a hundred commercial varieties with yellow cotyledons obtained 
from many different parts of the world, including the P34 type, 
also give the 13 : 3 ratio when crossed with P30 type. 
Studies of the Variation a the Boston Fern (Nephrolepis). By 
. BENEDICT 
Experimental work on Ween forms has been continued 
along the lines of previous years; namely, the maintenance of 
numerous bud variations for further observation, and the 
experimental raising and study of various lines derived from the 
spore-fertile strain. 
In this latter field the testing of disease susceptibility in one 
form has been carried out, involving the raising of a large number 
of plants. New cultures of other spore-fertile types have also 
been raised in considerable numbers. 
Systematic Botany 
The Classification of Dicotyledons. By ALFRED GUNDERSEN 
During 1925 I have continued studies relating to the general 
classification of dicotyledons. I have given chief attention to 
the question of the position of the herbaceous, apetalous dicoty- 
ledons, particularly the ‘‘Centrospermae’’ (Order Caryophyl- 
lales). Notes and drawings have been made of the structure of 
flowers and flower buds, and of seeds and ovules of certain groups. 
Forms of the Families Caryophyllaceae and Portulacaceae have 
been compared with forms of Families of the Order Parietales, 
such as Frankeniaceae, Elatinaceae, and Tamaricaceae. Among 
these groups numerous corresponding structures appear, in 
particular pearly ovules and rather long funiculi are characters 
widely distributed. Evidence is accumulating that the Centro- 
spermae may be most naturally regarded as a branch from the 
Parietales, while the Parietales, with frequent spiral arrange- 
ment and other characters, must be considered as very near the 
Ranales. 
