The problem with platyphyllum is that it goes along with primulinum and spicerianum...
In the 90's AnTec did a cross of stonei x kolopakingii, a part went to Florida to be grown for them as well. From those plants, a lot of 'platyphyllum' were selected and spread around the world, not by AnTec.
The real platyphyllum was known as 2 plants, though there were at least 2-3 more that existed at a point.
https://www.orchid.or.jp/orchid/people/tanaka/orchid/org/shinshu/enshinshu41.html
'Ruth Kennedy' was selfed a couple of times in the 90's. It has quite short, very wide leaves, a bit stoneish, and rough on the surface like a stonei. The selfings were not that vigorous, except for a few oddballs...
The bulk of platyphyllum came from those stonei x kolopakingii hybrids in fact. The cross is registered as Mem. Albert Eickhoff. It was done both ways, stonei x kolo, and kolo x stonei, and both with kolopakingii and topperii type as 'kolopakingii'.
Now to recognize if it is the artificial hybrid or platyphyllum, that's easy:
- Ruth Kennedy had shorter, wide leaves
- The dorsal back color of it and its selfings is white
- There are brown/dark stripes in the dorsal.
Similar to the picture of Dr. Tanaka website.
That was constant in all Ruth Kennedy progeny, which was the only ever propagated platypyllyum. Before, it was known as stonei var. latifolium. The real platyphyllum is very rare in cultivation.
The hybrids usually have either a greenish dorsal, or faint lines only in the dorsal, plus some have floppy leaves like kolopakingii too.