260 BOTANICAL GAZETTE [MARCH 
The interseminal scales and megasporophylls (stalks bearing terminal ovules), 
however, are of the Bennettites type, but much simpler in structure, although 
some of the simplicity may be due to immaturity. 
It is refreshing to obtain the following statement from an English paleo- 
botanist: ‘‘The morphology of the Bennettitean flower is still a problem to 
be solved, and the attractive hypothesis that would have us regard this domi- 
nant group of the Mesozoic era as a guide to the evolution of the class which 
now occupies the pre-eminent position in the vegetable kingdom, requires 
to be substantially strengthened before it can claim to have solved the mystery 
of the origin of the flowering plants.” —J. M. C 
Cytology of seedless oranges.—Osawa” has ee a the cytological 
situation in the two seedless oranges known as the ‘ ington navel’’ 
(Citrus aurantium) and the ‘‘Unshu” (C. nobilis), iyo using C. trifoliata 
as a check species. After showing that spermatogenesis and oogenesis in 
C. trifoliata are as usual among angiosperms, he finds in both the seedless forms 
a strong tendency toward the disorganization of pollen mother cells and 
megaspores. In the “Unshu’’ there is every stage in the failure of pollen 
development from a failure in the differentiation of sporogenous tissue up to 
the reduction divisions. In the majority of cases, however, pollen grains are 
produced. In the “Washington navel,’ spermatogenesis in the majority ot 
cases does not proceed beyond the mother cell stage. In both forms oogenesis 
usually proceeds to the formation of megaspores and then fails. As some 
normal embryo sacs are produced a few seeds were obtained; and the usual 
failure of seeds is due chiefly to the failure of embryo sacs rather than of pollen 
grains, especially in the case of the “Unshu.” The chromosome numbers 
in this form are 8 and 16. In C. #rifoliata it was discovered that fertilization 
occurs about four weeks after pollination, and the fertilized egg divides three 
or four weeks after fertilization —J. M 
Pine-barrens of New Jersey.—A careful examination of geological 
evidence leads TAYLOR” to the conclusion that the pine-barrens of New Jersey 
coincide in distribution with the geological Beacon Hill formation, an area that 
as been uninterruptedly out of the water since the Upper Miocene, and has 
several times been more or less completely surrounded by water. This would 
make this plant formation by far the oldest in New Jersey. Its xerophytic 
character does not appear to harmonize well with such a theory, although the 
number of more or less endemic species would seem to demand a rather com- 
plete and extended period of isolation such as the submergence and glaciation 
20 Osawa, I., Cytological and experimental studies in Citrus. Jour. Coll. Agric. 
Tokyo 4:83-116. fig. I. pls. 8-12. 1912. 
2t TAYLOR, NoRMAN, On the origin and present distribution of the pine-barrens of 
New Jersey. Torreya 12:229~-242. 1912. 
