Genus Campsis has been confusing me a lot for quite some time. Traditionally two species of this genus are recognized as common garden trumpet creepers:
Campsis grandiflora: leaflets 7-9; glabrous beneath; 4-7 cm long, paler green; calyx 5-lobed to middle; flowers orange to scarlet, corolla tube nearly one and half times as long as calyx, limb nearly 5-6 cm across; capsule 10-15 cm long, obtuse at apex, without beak.
Campsis radicans: leaflets 9-11, pubescent beneath especially along midreib and main veins, dark green above; calyx shortly 5-lobed, lobes less than 1/3 the tube; flowers orange with scarlet limb, 2-3 times as long as calyx, usually less than 4 cm across; capsule cylindric-oblong, 7-12 cm long, keeled along sutures, beaked at apex.
Campsis x tagliabuana: leaflets 7-11 (-13), glabrous beneath; calyx parted up to middle; flowers orange to scarlet; corolla tube 2-3 times longer than calyx, limb 5-8 cm across; sterile flowers fall off when mature, fruits not produced.
I have been following the specimens of Campsis in Delhi, Kashmir, California and other places and frankly have not been able to locate a true sample of C. gandiflora. Most of the samples found in Kashmir and Delhi which look like C. grandiflora do not bear fruits, flowers fall off when mature and number of leaflets varry from 7-11 (-13). This sterile hybrid is actually C. X tagliabuana, a hybrid between C. radicans and C. grandiflora. Both specimens at at FOI (C. radicans as well as C. grandiflora) i think belong to this hybrid species, which is propagated by cuttings.
Uploading C. x tagliabuana from Kashmir, very commonly growing in gardens and private houses. This hybrid species has a number of cultivars. This one from Kashmir is 'Madam Galen'
Dr. Gurcharan Singh
Retired Associate Professor
SGTB Khalsa College, University of Delhi, Delhi-110007
Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018.
Phone: 011-25518297 Mob: 9810359089