Thursday, September 10, 2020

[Botany • 2020] A Revision of the florbella group of Miconia (Melastomataceae, Miconieae) with Description of Three New Species: Miconia cava, M. florbella & M. valenzuelana


Miconia valenzuelana Michelang. & R.Goldenb. 

in 
Michelangeli & Goldenberg, 2020. 

Abstract
The florbella group of Miconia is composed of four species from the central Andes that are characterized by hollow stems inhabited by ants, and pleiostemonous flowers with a calyptrate calyx. The four species are M. inusitata, and the newly described here M. cava, M. florbella, and M. valenzuelana. The combination of pleistemonous flowers and calyptrate calyces suggests that these species could be placed in the former Conostegia, but at least three of the four species discussed here (M. florbella, M. inusitata and M. valenzuelana) do not belong in that clade and are more closely related to other species of Andean Miconia. All four species grow in undisturbed areas in low- to middle-elevation forests in the Andes.

Keywords: Calyptrate calyx, Conostegia, Florbella, Ecuador, mymercophyly, Peru, pleiostemony


Fig. 1: Miconia cava.
A. Fertile branch. B. Details of stem with ant holes. C. Detail of inflorescence. D. Flower bud with calyptra removed and calyptra with longitudinal section of the apex. E. Detail of flower apex in bud with the calyptra and proximal petals removed showing inflexed anthers and stigma. F. Flower bud in longitudinal section with the calyptra removed and ovary in cross section. G. Anthers in lateral and top views. (All from Gentry 80,167, NY.)

Miconia cava Michelang. & R. Goldenb., sp. nov. 

Etymology.—The specific epithet refers to the hollow nature of the young terminal branches.


Fig. 3: Miconia florbella.
A. Fertile branch. B. Inflorescence peduncle and first internode, both with ant holes and broad, hollow axes; detail of stigma on the left. C. Flower bud, lateral view. D. Flower bud, with the calyptra cut in longitudinal section (L) and fully detached (R). E. Petals (L) and flower bud with the calyptra and proximal petals removed. F. Stamens in lateral, ventral and dorsal views. G. immature fruit in longitudinal section. H. Fruit in cross section. I. Detail of fruiting branch. (A–G, from Perea 110, NY; H, from Rojas 8961, NY; I, from Foster 8646, MO.) 

Fig. 4: Miconia florbella in the field.
 A. Flowers at anthesis. B. Immature fruits (note flattened anthopodium) and leaves, adaxial surface. C. Immature fruit in cross section. D. Stem with ant opening. E. Hollow stem in longitudinal section and Myrmelachista ant. F. Leaf, abaxial surface.
(A, from Foster 10,920, photo by R. Foster; B–F, from Michelangeli 2823, photos by F. A. Michelangeli.)

Miconia florbella Schnell ex Michelang. & R.Goldenb., sp. nov. 

Etymology.—The specific epithet is taken from the generic name that Schnell (1996) planned to give this species in his unpublished thesis. Florbella is a combination of the Spanish words for flower (flor) and beautiful (bella).


Fig. 10: Miconia valenzuelana in the field.
 A. Stem with ant orifice (notice longitudinal ridges on the internodes). B. Hollow stem in longitudinal section with Myrmelachista ant. C. Flowering branch with young inflorescence. D. Inflorescence. E. Flower bud showing dehiscing calyptra. F. Flower at anthesis. G. Flower at anthesis. H. Immature fruits
(A–B, from Michelangeli 2825, photos by F. A. Michelangeli, C–H, from uncollected plants, photos by G. Gerlach.)

Miconia valenzuelana Michelang. & R. Goldenb., sp. nov. 

Etymology.—This species is dedicated to Peruvian Botanist Luis Valenzuela Gamarra, whose plant collections, including one of the paratypes of this species, have greatly augmented knowledge of the flora of Peru.


Fabián A. Michelangeli and Renato Goldenberg. 2020. A Revision of the florbella group of Miconia (Melastomataceae, Miconieae) with Description of Three New Species.  Brittonia. DOI: 10.1007/s12228-020-09633-w