You raise an interesting question, Beth. The issue of iconography in royal portraits is indeed intriguing.
Holbein pays as much attention to the details of jewellery as to the structures and patterns of fabrics. His portrait of Anne of Cleve to present her as a possible future bride for Henry VIII shows her dress adorned with flower-shaped medaillons - difficult to say if they could have been intended as Tudor roses in an anticipation of her prospective status (the one in the centre certainly doesn't look like a rose)
Anne Boleyn's portrait shows a piece of jewellery around her cleavage similar in style to the other examples, but the elements alternating with pearls are not flower-shaped:
And here's a later example, the portrait of Margaret Howard, daughter of Hernry Howard, Earl of Surrey, and wife of Henry Scrope, 9th Baron Scrope of Bolton. The jewels in her hair and the elements in her pearl necklace are similar to those of the Tudor queens and princesses 30 years earlier, but resemble more quatrefoils than roses: