Which Calendula is Medicinal?

We purchased the 'Standard Pacific' [variety] and would like to know the medicinal value of this. We chose the Calendula officinalis strain for this reason but notice that the flowers are all different. Could you help me here? Are they all medicinal or only certain ones?

All Calendula officinalis flowers have some medicinal value. The commercial calendula herb consists of yellowish-red ligulate florets of the yellow varieties, especially the double ones. So if you are growing calendula for the commercial dried herb market then you should choose the 'Erfurter Orangefarbigen' variety. The 'Standard Pacific' variety is medicinal too so there is no reason why it cannot be used also.
The ligulate flowers are arranged like petals around the perimeter of the flowerhead while the less medicinal, and smaller, tubular flowers are in the centre. Commercially acceptable calendula has no more than 5% sepals (the green petal-like appendages at the base of the flowerheads) and only occasional fruits (i.e. seeds). For more information on the qualitative and quantitative standards for commercial calendula, please consult Max Wichtl's "Herbal Drugs and Phytopharmaceuticals" (available from Richters; see www.richters.com/Web_store/web_store.cgi?product=XB5053