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MEIOSIS IN GODETIA
325
bouring chromosomes; möre öften they are lying in small groups
(fig. 5).
At anaphase 1 the I’s lag in Ihe plate and |hey divide when Ihe
paired homologues are ön their way to the poles (fig. 7); it was
some-limes possible to observe 9 small half chromosomes going to each pole
(fig. 8). Thus the behaviour of Ihe I’s in Ihe triploid hybrid is similar
to that in the triploid deflexa hybrid. Bul in the Bottae hybrid anaphase
1 often is disturbed. In fig. 8 t wo large chromosomes lag at the
equa-torial plate, they are Whitneyi chromosomes. In fig. 9 there is Iiiree
such large I’s. Whitneyi I’s divide låter than the small I’s, their division
seems to meet difficuUies and there is sometimes a slender bridge
between t wo chromatids going to opposite poles. The spindle often is
curved (fig. 9) and sometimes a restitution nucleus is formed from a
curved spindle (fig. 12), hut also several smaller nuclei may be formed
from such a spindle (fig. 13). Interkinesis presents a verv variable
picture (fig. 10—16). This variability is a result of the disturbances
at anaphase 1 and also of certain changes in the spindle and the
cyto-plasm of Ihe p.m.c., that tend to move lagging chromosomes, bridges
and nuclei in centrifugal directions to the vicinity of the wall of the
p.m.c. (compare Håkansson 1946). A peculiar feature in this hybrid
is that often formation of nuclear membranes occurs with a different
speed in different chroniosome groups (see fig. 11).
The second division often had a rather irregulär aspect.
Eliminated small or möre rarely large chromosomes or chromatids are often
seen, and small Bottae chromatids are scattered ön the spindles
(fig. 17). When an interkinesis nucleus divides a plate is readilv formed
hui Ihe Bottae chromatids seem to meet difficulties to arrange
them-selves in Ihe plate. lf we compare their behaviour with the behaviour
of the large deflexa chromatids in the triploid Whitneyi’X.deflexa
hybrid a difference seems to exist. At metaphase 2 the larger chromatids
were mostlv lying in or rather near Ihe plate, the smaller Bottae
chromatids were möre often at a greater distance from the plate, often lying
at Ihe poles of the spindles (fig. 17).
At anaphase 2 elimination of lagging chromatids is frequent, and
in some cases a bridge was observed (fig. 18). After meiosis Ihe
p.m.c. or young pollen cells often contain eliminated small chromatids
and fragments of chromosomes. Rarely a pollen diad was observed
(fig. 19).
It is clear, that I’s behave in a different männer in the triploid
hybrids between G. Whitneyi and G. deflexa-Bottae than in the diploid
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