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SVENSK BOTANISK TIDSKRIFT. 1923. Bo. 17, H. 4.
A PRELIMINARY NOTE ON THE CYTOLOGY OF
NICOTIANA SPECIES AND HYBRIDS.
BY
THOMAS HARPER GOODSPEED.
For over fifteen years a collection of species and varieties of
Nicotiana has been grown in the University of California Botanical
Garden and genetic investigations of a variety of sorts have been
carried on, the resulls of which have been published in the Uni-
versity of California Publications in Botany, volumes 5 and 11
and elsewhere.
To a preliminary list of chromosome numbers in Nicotiana al-
ready published there is little to be added at this time. Some
further examination has been made of N. alata, longiflora and
suaveolens and the following amended list of chromosome numbers
includes the results of these studies.
x 9 — N. Langsdorffii.
x8,3950r,.1 02 Nealata:
x 10 — N. longiflora.
x12 — N. sylvestris, glauca, glutinosa, paniculata, acuminata.
x18 — N. suaveolens.
x 24 — N. Tabacum, rustica, Bigelovii, nudicaulis.
In -fig. 1 are shown homotypic anaphases of alata, in b three |
of the four plates with nine chromosomes in each and in a all
the four plates two of which are made up of eight chromosomes
and the other two of ten chromosomes. Failure of conjugalion
in the case of one chromosome pair will account for this latter -
condilion. P. M. C. in this stage showing two anaphase plates
with nine and two plates with ten have been observed as well as |
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