Question mark in triangle in place of punctuation marks in email

Here's situation:

I'm on MacBook Air with Mavericks. My friend is on MacBook with previous OS(10.8). I write her from Mac Mail, she replies from a free web mail program (Juno). When she replies back to answer my email and I scroll down to see something I wrote to her, in my email now appears black triangles with a question mark in the middle of the triangle in each area where I had originally placed either commas or apostrophes. It seems the periods are fine. I think a dash mark is replaced also. So what is the reason and how to prevent it? Is it a Mavericks thing? Is it her email program? If its hers then why did it change on iphone-see next:

Here's a secondary situation: I'm now writing from iPhone (vs 6.1.4) and the same email came into this ph showing square empty boxes (outline of a box) instead of triangle & question mark, in the same location! What gives?