Monographs Details: Maguireanthus ayangannae Wurdack
Authority: Maguire, Bassett & Wurdack, John J. 1964. The botany of the Guayana Highland--Part V. Mem. New York Bot. Gard. 10: 1-278.
Family:Melastomataceae
Description:Latin Diagnosis - Simplicaulis erecta ad 25 cm alta; caulis petiolis laminis inflorescentia hypanthiisque dense stellato-puberulus, pilis pallidis ramulis plerumque 4-6 gracilibus ca. 0.3 mm longis. Folia opposita aequalia; petioli 1.5-5 cm; lamina 8-12 X 6-8 cm ovata apice hebeti-acuta basi plerumque truncata membranacea, supra sparsissime strigulosa pilis simplicibus ad 1 mm longis ad margines undulato-denticulata et ciliolata ciliis simplicibus 0.3-0.4 m m longis et 1-2 mm inter se distantibus pubescentia alioqui stellata, 7-plinervata jugis 1-2 mm et 3-8 mm et 7-19 mm supra basim insertis supra planis et glabris subtus leviter elevatis nervulis laxe (ca. 4 X 4 mm) reticulatis. Pedunculus 2-8 cm longus apice cum ramis duobus recte divaricatis secundifloris 2.5-10 cm longis. Flores 5-meri breviter (ca. 1 mm ) pedicellati; hypanthium (ad torum) 2 x 3.5 mm (alls exclusis) 10-alatum alls antesepalis ca. 1 mm et intersepalis ca. 0.3-0.5 mm eminentibus; calycis tubus 1 m m altus, lobis 0.8 X 1.5 mm late triangularibus apice late hebeti-acutis. Petala 5.4-5.8 X 2.3-2.4 mm spathulata apice hebeti-acuta glabra non ciliata. Antherarum thecae 2.3-2.4 mm longae basim versus attenuatae apice 0.5 mm latae poro 0.25 mm diam, connectivo sub thecis ad filamenti insertionem 0.8 mm prolongato dorsaliter cauda 0.3-0.4 mm longa lanceolata hebetiacuta descendente ornato; filamenta 3-3.1 mm longa glabra. Stylus 6.2 X 0.4-0.6 mm glaber; stigma 0.6 mm diam vix expansum truncatum; ovarium glabrum apice in collum carnulosum 0.4-0.5 mm altum prolongatum. Fructus ca. 5 mm longus; semina 0.6 X 0.25 mm anguste pyramidata imperspicue papillosa.

Discussion:

Fig. 66, d-i.

Type. Herb, flowers white, occasional in creek beds, montane slopes of Mt. Ayanganna, British Guiana, alt. 1000-1500 m, 5-6 Feb 1955, Bassett Maguire, W. M . C. Bagshaw, & Celia K. Maguire 40579 (holotype US 2342569).

The general aspect of Maguireanthus, along with the ventrally exappendiculate stamen connectives, suggests Bertolonia or Salpinga; neither of these genera shows the relatively long connective prolongation nor the anther shape of the new genus. Although habit variation within Macrocentrum is great, the connective prolongation is always much shorter than the dorsal appendage. In both pubescence type and inflorescence, Maguireanthus differs from all other Bertolonieae.