This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Distinguished from the neighbouring genera by the short calyx-tube and the three often recurved styles. Passion-flower is simply a translation of the technical name, which was given on account of a fancied resemblance in the parts of the flower to the instruments of Christ's suffering.
1. P. carulea (fig. 112). - The only hardy species, and even this requires the protection of a wall and covering in very severe weather. The petals vary in colour from white to pale blue and rosy-red, and the fringed corona and centre of the flower is differently coloured in different varieties. It frequently ripens its fruit in this country. This is. about the size and shape of a small hen's egg, changing from green to orange, and ultimately scarlet. The flowers are produced very freely, especially in the neighbourhood of the sea. It is a native of Brazil.
Fig. 112. Passiflora caerulea. (1/4 nat. size.)