Alibertia triloba Steyerm.

• Authority

  Maguire, Bassett. 1965. The Botany of the Guayana Highland. Mem. New York Bot. Gard. 12 (3): 1-285.

• Family

  Rubiaceae

• Scientific Name

  Alibertia triloba Steyerm.

• Type

  Type. Tree to 3 m ; leaves thin, coriaceous, slightly brittle, dark green above, lighter beneath; calyx and corolla-tube green; corolla-lobes white, 3, slightly fragrant; frequent in mixed evergreen forest between first and second cliffs, along northeast side. Mount Ayanganna, Upper Mazaruni River basin, British Guiana, at alt. 900-1100 m, 7 Aug 1960, S. S. Tillett, C. L. Tillett & R. Boyan 45180 (holotype NY).

• Description

  Latin Diagnosis - Arbor 3-metralis; stipulis persistentibus ovato-oblongis obtusis 1.5-4 mm longis, substrigosis vel glabris; foliis petiolatis, petiolis 6-8 mm longis; laminis coriaceis ellipticis apice abrupte obtuseque caudatis, acumine 10-13 mm longo spatulato-rotundato, basi manifeste angustatis, 9-10.5 cm longis 4.5-5 cm latis, utrinque glabris, nervis lateralibus utroque latere 7-8; inflorescentia masculina breviter pedunculata, pedunculo 1-1.5 mm longo, 3-9-flora, ramis seeundariis ad 2.5 mm longis; florium masculinorum flori centrali sessili, ceteris pedicellatis, pedicellis glabratis 1-1.5 mm longis; calyce masculine 2 mm alto 2 mm lato apice truncato vel minute repando, extus intusque minute puberulenti, margine ciliolato; corollae tubo 9-11 mm longo 1.5 mm lato anguste cylindrico, extus dense cano-pulverulenti intus glabro subpapillato, lobis 3, interdum 4, ovato-lanceolatis acuminatis 7.5 mm longis 2.5 mm latis extus puberulentibus intus glabratis; antheris tribus 5 mm longis supra basin corollae 1.5 mm insertis.

• Discussion

  This species is unusual in having a 3-lobed (rarely 4-lobed) corolla of the staminate flower. From A. myrciifolia it differs further in the denser buff tomentum on the outer surface of the corolla-tube, shortly pedunculate staminate inflorescence with secondary branched axes, and pedicels up to 2.5 mm long.