THE FORMATION AND DEGENERATION OF GERM CELLS IN 
THE POTATO 
W. J. Young 
(Received for publication October 9, 1922) 
No information seems to be available on the cytological characters 
and germ-cell formation of the potato. Investigators who have undertaken 
preliminary work of this nature have found the subject unfavorable for 
study and have abandoned the project. The unfavorable characters are the 
small size of the cells and other structures, as a consequence of which it 
is difficult to make out the details, and the degenerative changes which 
occur in the germ cells and in associated structures as a result of congenital 
causes or of unfavorable conditions of environment. 
The present study was carried out in connection with the Irish-potato- 
breeding project at the South Carolina Agricultural Experiment Station 
and is presented as a contribution from the Department of Horticulture 
of that institution. This paper is intended as a supplement to the material 
presented in Bulletin 210 of the Station, entitled, “Some Phases of Breeding 
Work and Seed Production of Irish Potatoes.” The primary object of the 
work is to follow the degenerative changes in the germ cells on account of 
the bearing which such changes might have upon the failure of most potato 
varieties to set seed. As a matter of record and for purposes of com¬ 
parison, the normal development of the floral structures and of the germ 
cells is described and figured in so far as these structures could be made out 
and as the available material permitted, although they conform quite closely 
to typical cases. 
Development of the Flower 
The flowers arise as small rounded masses of cells (text fig. 1,1), which 
soon become broad and somewhat flattened at the top. The calyx originates 
at an early stage (text fig. 1, 2) as a marginal ring having five lobes. Con¬ 
siderable development of the calyx takes place before the differentiation of 
other floral structures, enclosing the broad, flattened, and slightly convex 
receptacle in a low, conical cavity (text fig. 1,3). The petals and stamens 
appear to arise simultaneously as upright lobes from the margin of the 
receptacle (text fig. 1 ,4). The petals are much thinner than the stamens 
and grow more rapidly. Their growth is less upright than that of the calyx, 
and the margin becomes somewhat incurved so that the cavity which they 
inclose becomes quite broad and flat. The pistil arises as a circular ring 
of tissue within the circle of stamens (text fig. 1,5). Soon growth begins 
in the central part of the receptacle, forming the placenta (text fig. 1, < 5 ), 
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