80 BOTANICAL GAZETTE 
young cell walls. The existence of Plasmodesmen between the symbiont 
cells in grafts of Abies and Picea is shown conclusively. Such facts as thata 
grafted shoot does not produce roots at its base, and that a grafted lateral 
twig may bend up and replace a lost central shoot, are doubtless due 
morphaesthesia, the stimuli being transmitted through the Plasmodesmen 
the graft. The question as to whether the Plasmodesmen involve continuity or 
only contact of fibers sent out from adjacent cells is fully discussed, but 
to technical difficulties the facts in the case remain undiscovered.—* * + 
HucGo MIEHE™* has recently investigated certain cases of nuclear migra- 
tion in the epidermal cells of some monocotyledons. The fact of the polarity 
of the epidermal cells that form stoma mother cells had been established 
ends of the Jeaves directed outward on the centrifugal machine, the polarity 
of the cells be — reversed, Zz. é., the stoma mother cells are formed 
bulbs were left adhering, and allowing them to grow for some time 
favorable conditions, the consequent change in the direction of cell g 
the stoma cell under ordinary conditions. 
Perhaps the most interesting part of the paper, however, is the 
of the migration of the nuclei from cell to cell, a process that Miehe 
to occur as a response to the stimulus produced by wounds. In such 
the nuclei. migrate toward the wounded cells, and when they come 
cell walls put out fine processes that protrude through minute pores 
wall. di lanes nucleus passes through such a pore and forms 2 
_ ‘mass 1e OPE of the wall. From the fact that in material k® 
_in Flemming’s fluid and stained with the triple stain the denser part ~ 
| nucleus. foi OU the pointed processes and the part that has 
ceued a 
_ Miehe supports Fischer’ s contention that differentiation in staining 
largely to differences i in physi ical rather than chemical structure of the 
: * Ueber Wanderungen des — Zelikernes. Flora 88: 105-14 
— 
- = Ein Bets zur  twistlanagecihe der Spaltéffnungen. 
_ Bot. 6 2301. 1 
: , u. experimentelle Untersuchungen aber die ‘Anlage ’ 
grins einige pees Bot. Centralb. ets 321, 353, on 1899. 
