Passiflora alata, P. x decaisneana, P. phoenicea and P. quadrangularis comparison

Passiflora alata

Passiflora alata – quite like Passiflora quadrangularis but smaller flowers. A very variable species.
Square stemmed. 2-4 petiole glands per petiole. Stipules 1-2cm long by 0.3-1cm wide. Single lobed ovate leaves
Flowers 10-12cm wide with neat corona filaments. Sepals and petals red inside & green out.
Fruit ovoid, 10-15cm long by 5-10cm wide, bright orange or yellow when ripe.
Image © 2010 Stephen Gray More images

Passiflora x decaisneana

(Passiflora alata x Passiflora quadrangularis) often mislabelled and sold as P. quadrangularis. There are a number of clones of this cross.
Square stemmed. 4 glands on 90% of the petioles. Stipules 15mm long by 6mm wide. Large ovate leaves.
Heavy flowers 10-13cm, corona filaments a bit scruffy at the end compared with alata. Sepals and petals red inside & sepals green out & petals red out.
Fruit egg shaped up to 18cm long, dull orange when ripe.
Image © 2012 Martine Sanchez

A great selection by Patrick Worley, Passiflora phoenicea ‘Ruby Glow’ is widely available in cultivation. Often incorrectly known as Passiflora alata ‘Ruby Glow’. Image © 2012 João Franco
Square stemmed. 2 bright yellow petiole glands on the petiole, as below, near the leaf make ID easy. Especially obvious on new foliage. Coloraturas fades on mature leaves. Stipules 10-12mm long by 3-4mm wide. Large ovate leaves.
Flowers 11-13cm. Petals brick red outside & rich purple inside. Neat corona filaments. Sepals shorter than petals.
Fruit large ovate, up to 13cm long & 8cm diameter, yellow when ripe.
Image © 2012 João Franco

Passiflora quadrangularis A huge vine.
Square stemmed. 6 glands on 90% of the leaf petioles. Stipules 2-3.5cm long by 1-2cm wide.
Large ovate leaves. Flowers 8-12cm. Very scruffy corona filaments, sepals a little paler than petals inside.
Fruit quadrangular (four sided), 20-30 cm long by 10-20 cm wide, pale yellow-green when ripe.