1960] 



BOTANY OF THE GUAYANA HIGHLAND PART IV 



35 



liberis, petalis valde imbricatis, tubo inaequali conjunetis ; stamina fertilia 2, 

 antheris basim appendieulatis, dorsualiter in connectivo valde papillato-glandu- 

 latis, filamentis in tubo corolla cohaerentibus. Discus cupularis, quinquelobatus ; 

 stigmata quinquelobata ; ovarium quinquepartitum, carpellis solum stylo con- 

 junetis. Fructorum cocci monosperma, capsularia. 



Type Species: Myllanthus maroana Cowan. 



Mylldnthus is properly associated phylogenetically with two genera, Lubaria 

 and Raputia. All three genera are characterized by zygomorphic corollas; in 

 most of the species the corolla is more or less arcuate, and this characteristic is 

 the basis of the generic name of the new genus ( /xvAAo?, myllos — bent ; av0o<?, 

 anthos — flower). Lubaria is easily distinguished from the others by its free 

 adaxial petal with the two fertile stamens on the adaxial side of the flower ; the 

 other two genera (Myllanthus and those species of Raputia with appendaged 

 anthers and strongly arcuate corolla) have the abaxial petal more nearly free 

 than the other petals (but distinctly joined with the others at least basally) and 

 the two fertile stamens on the abaxial side of the flower. However, the basal 

 appendages of the anthers are very different in the Raputia species, consisting 

 of elongate, ligulate structures which are obviously the unmodified, sterile bases 

 of the anther thecae. At least two species of Raputia have the arcuate corolla 

 and the orientation of the androecium of Myllanthus, but in addition to the 

 difference in the appendages, the calyx of the Raputia species is cupular with 

 small teeth on the margin of the cup. 



Key to the Species of Myllanthus 



1. Leaflets oblong, three times as long as wide. Inflorescence 3-4 cm long, not obviously 



coiled. 1. M. maroana. 



1. Leaflets elliptic, less than three times as long as wide. Inflorescence 10-18 cm long, 



obviously coiled. 2. 



2. Leaflets with petiolules 1-2 cm long; petioles about 8 cm long. Flowers with pedicels 



3-4 mm long. 2. M. neblinae. 



2. Leaflets sessile; petioles 4 cm long or shorter. Flowers sessile or subsessile. 3. M. ulei. 



1. Myllanthus maroana Cowan, sp. nov. Fig. 22, a-d. 



Arbor 3-6 m alta, ramulis minute malpighiaceo-strigulosis sed mox gla- 

 bfescentibus, foliis digitato-trifoliolatis. Petioli 10-12 cm longi, glabri, canalicu- 

 lati, laminae sessiles, oblaneeolatae usque ad oblanceolato-oblongas, coriaceae, 

 discoloratae, infra pallidiores, glabrae et nigro-punctatae, 25-45 cm longae, 8-14 

 cm latae, acutae apicaliter, ad basim attenuato-cuneatae, costa salienti, venulis 

 pi an is supra, infra salientibus. Inflorescentiae cauliflorae, 3-4 cm longae, uni- 

 lateraliter cincinnoideo-racemosae, axe et floribus minute malpighiaceo-strigulosis, 

 pedicellis 4-6 mm longis. Sepala 3-3.5 mm longa et lata, orbicularia vol suborbi- 

 cularia, ciliolata ; petala villosa intus, inaequaliter connata, petalo abaxiali in tubo 

 ca. 4 mm connato, ejus lobo 15 mm longo, obtuso, petalis ceteris in labia quadri- 

 lobata, curvata ca. 11 mm longa connata, eorum lobis oblongis, leviter cucullatis, 

 ad apicem rotundatis. Stamina 4 sed solum 2 fertilia, filamentis elongato- 

 oblanceolatis, apicaliter subulatis, villosis ; antherae fertiles oblongae, connectivo 

 papillato-punctato, 5.5 mm longae, 1.5 mm latae, appendicibus late flabellatis, 

 antherae apicem versus curvatis et papillato-glandularibus, ca. 2 mm longis et 4 

 mm latis. Discus carnosus, ca. 1 mm profundus ; stylus 9 mm longus, glaber ; 

 ovarium glabrum, papillatum. Fructorum cocci oblongo-obovata, 17 mm longa, 

 10 mm lata, ad apicem dehiscentia; semina ca. 12 mm longa, 8 mm lata, ovali- 

 oblonga. 



