Monographs Details: Amphitecna regalis (Linden) A.H.Gentry
Authority: Gentry, Alwyn H. 1980. Bignoniaceae--Part 1. (Crescentieae and Tourrettieae). Fl. Neotrop. Monogr. 25: 1-130. (Published by NYBG Press)
Synonyms:Crescentia regalis Linden
Description:Species Description - Small pachycaul tree 4-12 m tall, to 15 cm dbh, the leaves in a terminal cluster, branchlets thick, rather angular. Leaves alternate-verticillate, congested near branch apex, oblanceolate, obtuse to acutish, cuneate-attenuate at base, gigantic, 69-100 cm long, 18-35 cm wide, subcoriaceous, glabrous, midrib conspicuously raised above and below, secondary veins plane above, barely prominulous below, whitish-margined, drying olive below, blackish-olive above, petiole not differentiated. Inflorescence cauliflorous, the pedicels glabrous, ca. 1 cm long. Flowers with the calyx bilabiate, circumscissilely caducous, bilabiately split to base, 2.5-2.8 cm long, each lobe ca. 1 cm wide, obtuse, glabrous; corolla white, tubular-infundibuliform, more or less radially symmetrical, 5.2-6.5 cm long, 2.3-3 cm wide at mouth of tube, the lobes fused into a frilly-margined rim, sparsely stalked-lepidote on outside of lobes, otherwise glabrous; stamens inserted 2-2.5 cm from base of tube, anther thecae slightly divergent, 6-7 mm long, the filaments 1.5-1.7 cm long; ovary conical, ca. 3 mm long, to 2 mm wide at base, densely minutely lepidote; disc annular-pulvinate, 1 mm long, 5 mm wide. Fruit unknown.

Discussion:Vegetatively the most obvious difference between A. regalis and its two pachycaul relatives A. macrophylla and A. megalophylla is the barely prominulous secondary venation of the leaf undersurface; its gigantic leaves are also apparently larger than in either of its two closest relatives. The corolla is broader and more infundibuliform and the calyx lobes shorter than in the similar flower of A. macrophylla; the small flower of A. megalophylla is completely different. Ecologically A. regalis is separated from the two related species by its lowland habitat.

I have previously placed C. regalis in the synonymy of A. macrophylla (Gentry, 1973b). To my knowledge, C. regalis otherwise has been universally ignored except for its listing in Index Kewensis. Linden’s obscure “sub-nudum” description of sterile material—“Arbuste majestueux a feuilles sessiles entieres, dures et coriaces, spatulées, longement atténuées, mesurant 3 pieds de longueur sur 10 pouces de largeur. C’est une plante a effet grandiose, et la digne rivale du Curatella (Theophrasta) imperialis.”—seems hardly adequate for identification. Nevertheless the very large leaves described for C. regalis fit only this species and Guatemalan A. megalophylla. There are two sterile collections of this species at the British Museum each consisting of a single leaf, identified as Crescentia regalis Linden and labelled as originating in Chiapas. One leaf is 82 cm long and 19 cm wide, the other 63 cm long and 16 cm wide. The larger leaf was collected by Ghiesbrecht from whom Linden obtained much Mexican material, and undoubtedly represents the plant brought into cultivation by Linden. I have designated it as the type of Crescentia regalis. The existence of 1878 and 1887 flowering collections labelled as C. regalis obtained from a cultivated plant at the Munich Botanical Garden and presumably deriving from Linden’s original distribution, further prove that Linden’s plant is indeed this rare Mexican species.
Distribution:Mexico North America| Chiapas Mexico North America| Oaxaca Mexico North America| Tabasco Mexico North America| Veracruz Mexico North America|

Common Names:Morro-cimmaron