Eric
Carnivore
D. x anglica is a natural hybrid of D. linearis and D. rotundifolia. It can be expected to be found where the latter 2 species grow together, basically where D. linearis is found. But D. x anglica is rare because it is sterile. And it is frequently overlooked because it looks just like the fertile D. anglica (amphiploid) when not in fruit.
D. anglica being a hybrid of D. linearis and D. rotundifolia that has undergone chromosomal doubling was already proposed by Winge (1917). Minor differences exist though. See the comprehensive article in Rhodora vol.57 by Wood (1955) for a full description.
Schnell (1999) published his view on differentiating the hybrid from the species in CPN.
To make it a bit more complicated you should remember that there is also the sterile hybrid D. x obovata (D.anglica x rotundifolia) which can be confused with D.anglica and especially with D. x anglica.
D. x anglica growing in a hollow of a floating bog. No D.linearis were found growing nearbye, but D. linearis does grow in this part of ON.
D. anglica being a hybrid of D. linearis and D. rotundifolia that has undergone chromosomal doubling was already proposed by Winge (1917). Minor differences exist though. See the comprehensive article in Rhodora vol.57 by Wood (1955) for a full description.
Schnell (1999) published his view on differentiating the hybrid from the species in CPN.
To make it a bit more complicated you should remember that there is also the sterile hybrid D. x obovata (D.anglica x rotundifolia) which can be confused with D.anglica and especially with D. x anglica.
D. x anglica growing in a hollow of a floating bog. No D.linearis were found growing nearbye, but D. linearis does grow in this part of ON.