PROPAGATION OF BLOWOUT PENSTEMON (PENSTEMON HAYDENII S. WATS) 239



(Table 2). Those plants fertilized with both nutrients produced
more breaks than those fertilized with one or no nutrient (p=
0.11). Perhaps the age of the seedling as well as its nutrient status
primarily determined the total number of axillary breaks produced,
rather than a pinching treatment.

Table 2. Effect of pinching and level of nitrogen and phosphorus fer-
tilization on mean total number of axillary breaks per seedling formed
after the pinching date.

Fertilization Level             Nonpinched      Pinched

                                    number of axillary
                             ----- breaks/seedling ------------
None                                1.1            1.3
One nutrient, N or P                1.9            1.8
Both N and P                       3.3            3.7
OVERALL                            2.1            2.3



                      CONCLUSIONS
  Nitrogen and phosphorus fertilization may be used to produce
vigorous blowout penstemon seedlings in the greenhouse, when
seedlings are grown on river sand. Pinching fertilized plants just
prior to transplanting outside may be desirable to stimulate growth.
These production methods could be used in the recovery and re-
establishment of blowout penstemon, Nebraska's only endangered
plant species.

                 ACKNOWLEDGEMENTS
  Appreciation is expressed to the Nebraska Game and Parks Com-
mission for financial support of the research on blowout penste-
mon. Journal Series Number 8412, Agricultural Research Division,
University of Nebraska.



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