Re: "Drosera * 'Nagamoto'

SCHLAUER@chemie.uni-wuerzburg.de
Wed, 28 Aug 1996 09:41:38

Dear All,

> >I bought a rosette sundew earlier labelled Drosera x Nagamoto. It has
> >flowered profusely all summer and has now set seed. Should this hybrid
> >set seed, and can I expect it to be fertile?
>
> Sounds like you got a mislabeled plant...... I wasn't under the impression
> that that hybrid was supposed to set seed.

Has anyone tested fertility in _Drosera_ hybrids besides _D.anglica *
rotundifolia_? In this special (2n=30) case sterility seems to be
pretty complete. From this finding it is frequently (and wrongly so,
v.i.!) inferred that *all* _Drosera_ hybrids should be sterile.
However, this hypothesis was very rarely tested further.

"Drosera * 'Nagamoto'" (not a regular cultivar name; AFAIK never
registered properly!) is an ambiguous name because the second parent
"D.spatulata", was in some cases not the pure species but the hybrid
_D.rotundifolia * spatulata_ (D.*tokaiensis, 2n=60). The "true"
D.* nagamotoi (_D.anglica * spatulata_) has 2n=40 chromosomes (like
both parents), while the one with the "Kansai" second parent
(_D.anglica * [rotundifolia * spatulata]_) has 2n=50 (like it is to
be expected if two species with 2n1=40 and 2n2=60, respectively, are
hybridized: n1=20 n2=30 -> n1+n2=20+30=50). This little example (cf.
Kondo & Segawa, La Kromosomo II-52-53:1702, 1988) proves that at
least the hybrid (or hybridogenic species) _D.rotundifolia *
spatulata_ (D.* tokaiensis, syn. D.* kansaiensis) is *fertile*. The
supposedly hybridogenic species _D.collinsiae_ is perhaps another
example of fertile hybrids in _Drosera_.

Any comments?

Kind regards
Jan