Venery under the rose

[Terrance]

Is there any evidence, artifacts to support any claims to
the origin of "sub-rosa"? The entry, David Morris, you
posted, is almost identical with that in Brewer's, I think
if I remember right, some painted jars and such were linked
by some scholars to Harpocrates, but, and I think Pynchon
was aware of this, the origin of the meaning of sub-rosa is
not known, what does the OED say?, not much I think,
etymologists, philologists, linguists, Classicists, scholars
of Egyptian, Greek, and Roman culture acknowledge, I
believe, that the origin simply cannot be confirmed.  I
think, is it R&J? , or is it Two Gentlemen?, Two Gentlemen,
where Shakespeare was onto this too, but in any event, I
think Pynchon milks it for all its worth, including of
course, the roses above the confessionals in the Church and 
in those stain glass windows, the symbol of the Virgin, that
Henry Adams, as tourist,  recorded. 

In any event, Sir Thomas Browne covers the meaning of "sub
rosa" in
'Pseudoxia  Epidemica', Book V, Chapter 22, subtitled
"Compendiously of
many  questionable customes, opinions, pictures, practises,
and
popular  observations", section 7. 

7. When we desire to confine our words we commonly say they
    are spoken under the Rose;13 which expression is
commendable, if  the Rose from any naturall propertie may be
the
symbole of silence, as Nazianzene seems to imply in these
translated verses. 

          Utque latet Rosa Verna suo putamine clausa,
          Sic os vincla ferat, validisque arctetur habenis,
          Indicatque suis prolixa silentia labris:

      And is also tolerable, if by desiring a secrecy to
words spoke under  the Rose, we onely meane in society and
compotation,
from the  ancient custome in Symposiacke meetings, to weare
chaplets of Roses about their heads; and so we condemne not
the
Germane  custome, which over the Table describeth a Rose in
the
seeling; but  more considerable it is, if the originall were
such as
Lemnius and others have recorded; that the Rose was the
flower of
Venus, which Cupid consecrated unto Harpocrates the God of
silence, and  was therefore an Emblem thereof to conceale
the
prancks of Venery, as is declared in this Tetrasticke: 

          Est Rosa flos veneris, cujus quo facta laterent
          Harpocrati matris, dona dicavit Amor;
          Inde Rosam mensis hospes suspendit Amicis,
          Convivæ ut sub ea dicta tacenda sciant.14