B2.5V

Walborn71 defines HD 214432 as its B2.5V standard, but its B3V elsewhere.
Garrison79 lists Sig Sgr as their B2.5V standard.
Walborn90 defines HD 148605 as its B2.5V standard, but its B2V elsewhere.
Skiff08 lists one B2.5V standard: HD 37016 (B2.5V; MK78)
Lesh68 lists HD 36779 as its B2.5V standard. 


None of the B2.5V standards has an excellent pedigree

Hiltner69 classified 24 stars as B2.5V, with the brightest HR 5812
(V=3.7).

# Standards
HR 1891 = HD 37016 (Orion)
  B2.5V: Jaschek78(Lesh68),MK78,GrayAtlas
  B2IV: Schild71
  B2V: Abt77
  B3V: Sharpless52,Jaschek64
  B0: Cannon
  B9III/IV: Houk99
  0.4" binary

# Weak Standard
HD 214432
  B2.5V((n)): Walborn71
  B2.5V: Levato76
  B3V: BlaauwMorgan53,Jaschek64(all),Jaschek78(JM53)
  B3: Cannon
  Mostly B3V, but Walborn calls B2.5V

HD 175191 = sig Sgr = HR 7121
  B2.5V: MK73,Garrison79(stan),Houk82
  B2V: Cowley72(stan)
  B3IV: Hiltner69
  B3: Cannon
  B4IV: Buscombe60,Morris61,Buscombe69
  Jaschek64 shows B3IV-V,B3V,B4IV,B4V
  Not very good agreement between authors. 

HD 148605 = 22 Sco = HR 6141
  B2V: Houk,MK73,GrayAtlas
  B2.5V: Walborn90
  M91: V=4.782+-0.007, B-V=-0.125+-0.020, U-B=-0.728+-0.026
  =>QBV=> (B-V)o=-0.211, (U-B)o=-0.772, E(B-V)= 0.086, T=20084.
  Morgan & Gray call it B2V, but Walborn90 uses it as B2.5V standard

HD 36779
  B2.5V: Lesh68(stan)

# Non-Standards
Alf Pav = HD 193924 = HR 7790
  B2.5V: Houk75(Hiltner69),Garrison96
  B2IV: Jaschek78(Levato75)
  B3IV: Wood55,Jaschek64(all)
  B3V: Gahm83
  B3: Cannon
  Never proposed as standard, and not a good candidate to be one either.

Zet CMa = HD 44402 = HR 2282 
  B2.5V: Buscombe69,Houk(Garrison96)
  B2.5IV: Jaschek78(Hiltner69)
  B3V: Jaschek64(most)
  B3: Cannon
  Never proposed as standard, and doesn't appear to be a good candidate to be one.