Here's the form with yellow anthers. Weird anthers! To my eye, they always seem to point away from what would make a well composed picture. And why partridge? This is a New World plant, partridges are Old World birds. What is a partridge anyway? Turns out they are the Eurasian equivalent of our quail. So what is one doing in a pear tree. Alliteration! Which may also explain partridge pea.