Yes been there, done that.
But for the sake of explanation and judging many of these (plus my intensive research and paper on the varieties of venustums), let’s elucidate further:
The initial discovery circa 1890’s of the ‘albino’ forms had these tiny spots in the base of the petals (2-3) and further line breeding produced ones with no spots and up to 10 spots (average 3-5 spots).
These spots were on the hairs or warts of the flowers, and were not part of the red anthocyanins on petal cells of the normal flower inheritance. This meant that they bred true as ‘albinos’ in yellow or alboviride progeny.
As a result, these alboviride forms with dark spots were considered by breeders and some taxonomists as the measuresianum forms.
If you want to get technical, the leaves of these albinoviride (with spots) do not have anthocyanins nor do these types produce colored type progeny when selfed.
In addition, even the occasional rarely found measuresianum flowers with no spots, when selfed, will produce green flowers with these spots in progeny.
Although some taxonomists and diehard fans champion the ‘albino’ term for var measuresianum, it really should be considered ‘alboviride’ as it’s a green flower and not white.
And finally… In almost every picture (but one) of books depicting this form, from Braeme to Grus, as well as awards from around the world, these spots were very much present.
I have now finally had some time to do a bit of homework - and, Leslie, I wouldn't in your shoes take recourse to invoke Braem's authority in this matter. Braem clearly and unequivocally asserts in the 2nd Edition of his comprehensive "The Genus Paphiopedilum", that " Plants offed as albinos of P. venustum sometimes show, although faintly, the remnants of reddish or brownish pigmentation. However, only those clones lacking any red or brown should be accepted as albinos" (p. 266, 2016). I can't distinguish any red or brown, however faint, in the photo in his book of this colour form (p. 389, ibid.).
Cribb in the 2nd edition of his monograph on "The Genus Paphiopedilum" is fully in accord with Braem's point of view: "... [A]lbino plants, referable to var. measuresianum, lacking any maroon or purple colour in the leaves and flowers are occasionally seen in collections ..... It is perhaps best treated as a form" (p. 392, 1998). Sadly, Cribb provides no photo of this colour form, but refers magnanimously to Braem (1988) for providing "[e]xcellent photo-graphs [sic] of this" (ibid.).
Gruß in his lavishly illustrated book on "The Genus Paphiopedilum. Albino Forms" shows photos of as well flowers without as with anthocyanin specks - but what the latters pertain, he clearly sees them as an abberation of the albino colour form, fma. measuresianum, as he explicitely makes the following qualifying statement in the photo caption: "shown as forma. alba [sic] but with black spots" (p. 181, 2008). A view that is fully in accordance with Gruß' overall concept of albinism in Paphiopedilums, which he presents in the introduction to the book (p. 8, ibid.).
I, too, believed that measurianum had no spotting but thats not clear from the original description.
Stephen might be right in assuming, that the original description was imprecise or lacking, but Leslie clearly errs, when he states:
The initial discovery circa 1890’s of the ‘albino’ forms had these tiny spots in the base of the petals (2-3) and further line breeding produced ones with no spots and up to 10 spots (average 3-5 spots).
Braem quotes an anonymous, contemporaneous source on the November 28th, 1893, meeting of the Royal Horticultural Society, where Measures exhibited the colour form for the first time: "an extraordinary and beautiful form with white and green flowers, without any of the brown and red seen in the type" (p. 266, 2016).
I hereby rest my case. And henceforth I will discount my plant from belonging to the realm of that treasured botanical colour form, 'fma. measuresianum' - resigning myself to the use of the horticultural epithet 'fma. alboviride (Hort.)'.
Most Sincerely,
Yours Waldorf