The only way I know of to tell P. "Weser" from P. "Sethos" is the flower.
Edit:
N: $[Pinguicula ' Sethos ' {Hort.Slack}]
P: Insect-Eat.Pl. & How to Grow Them:113 (1986)
S: =[[Pinguicula ehlersiae {Speta & Fuchs}] * [Pinguicula moranensis {H.B.K.}]]
HC: Registered 10. 11. 1998 (JS)
B: H.Weiner, Hameln, 1981
Nominant: H.Weiner
Registrant: A.Slack
Description: Insect-Eat.Pl. & How to Grow Them:113 (1986)
"Of these (hybrids) I would mention [Pinguicula ' Sethos ' {Hort.Slack}] ([[Pinguicula moranensis {H.B.K.}] * [Pinguicula ehlersiae {Speta & Fuchs}]]), a fine, very floriferous clone with large orchid-purple flowers with a many-rayed mouth like a white star; [Pinguicula ' Weser ' {Hort.Slack}], of the same parentage and with rather similar flowers, has a solitary white streak down the central lower lobe and dark veins."
Standard: {Oliver Gluch}
Etymology: obscure (perhaps alluding to a Pharaoh)
and
N: $[Pinguicula ' Weser ' {Hort.Slack}]
P: Insect-Eat.Pl. & How to Grow Them:113 (1986)
S: =[[Pinguicula moranensis {H.B.K.}] * [Pinguicula ehlersiae {Speta & Fuchs}]]
HC: Registered 10. 11. 1998 (JS)
B: H.Weiner, Hameln, 1981
Nominant: H.Weiner
Registrant: A.Slack
Description: Insect-Eat.Pl. & How to Grow Them:113 (1986)
"Of these (hybrids) I would mention [Pinguicula ' Sethos ' {Hort.Slack}] ([[Pinguicula moranensis {H.B.K.}] * [Pinguicula ehlersiae {Speta & Fuchs}]]), a fine, very floriferous clone with large orchid-purple flowers with a many-rayed mouth like a white star; [Pinguicula ' Weser ' {Hort.Slack}], of the same parentage and with rather simiar flowers, has a solitary white streak down the central lower lobe and dark veins."
Standard: Insect-Eat.Pl. & How to Grow Them:114 (1986)
Etymology: after the river at originator's locality
Note that both P. 'Sethos' and P. 'Weser' are a cross of [[Pinguicula moranensis {H.B.K.}] * [Pinguicula ehlersiae {Speta & Fuchs}]]. The distinguishing characteristic of P. 'Weser' is "large orchid-purple flowers with a many-rayed mouth like a white star" and for P. 'Sethos'; "of the same parentage and with rather simiar(sic) flowers, has a solitary white streak down the central lower lobe and dark veins."