Abstract Detail

Anatomy and Morphology

Quintanar, Angelica [1], Pace, Marcelo [2].

Unraveling the diversity of habits in Bunchosia clade (Malpighiaceae) through its anatomy: Echinopterys as a case study.

Within Malpighiaceae, the Bunchosia clade is composed of six genera (Bunchosia, Echinopterys, Heladena, Henleophytum, Thryallis and Tristellateia), with great morphological diversity and distributed in a wide diversity of habitats. However, what anatomical changes these plants have undergone in both these habitat transitions and growth form transitions is yet unknow. Despite the evident relationship between stem anatomy and habit, there is meagre information on the patterns of anatomical evolution during habit transitions. One of the most enigmatic genera within the Bunchosia clade is Echinopterys, a Mexican endemic group of erect or scandent shrubs that unlike the rest of neotropical Malpighiaceae, lacks sepal glands. Despite a good general morphological characterization of the genus, nothing is known about its anatomy, and how it can unveil traits related to the evolution of growth forms in the clade. Here we attempt to make an anatomical description of Echinopterys eglandulosa, a scandent shrub found in tropical deciduous forest, desert scrubs and other seasonally dry habits, and compare its anatomical structure with other genera found within the clade, whose growth forms and habits are different. The wood anatomy of Echinopterys eglandulosa is characterized by vessel elements arranged in a radial-dendritic pattern in its self-supporting region, while forming tangential vessel bands in its scandent region, multiple radials of 2-4 in the first and generally solitary vessels in the latter; axial parenchyma aliform, confluent and banded, rays of two different heights, multiseriate, with prismatic crystals inclusions. In the phloem the sieve tubes elements have one companion cell lying on the sieve tube corner, as seen in transverse section, the rays have a straight course and druse inclusions, the sclerenchyma is composed of sclereids, which are either clustered or in bands. Unlike the genus Bunchosia, commonly represented by trees and shrubs, and Thryallis composed only of lianas, which are in the same subclade of E. eglandulosa, the latter present a mix of characteristics commonly seen in shrubs and trees but with vessel elements of different diameters typical of lianas such as Thryallis. This work is the first part of a broad study that seeks to understand the evolutionary patterns vascular system diversification in the group, combining information from anatomy and ontogeny within a phylogenetic framework; considering the types of habit and habitat they have.

1 - Instituto de Biologia, Universidad Nacional Autonoma de Mexico, Posgrado en Ciencias Biologicas, Cto. Zona Deportiva S/N, C.U., Coyoacan, Mexico City, DIF, 04510, Mexico, Mexico City, EX, 04510, México
2 - Universidad Nacional Autonoma de Mexico Instituto de Biologia, Botanica, Circuito Zona Deportiva sn de Ciudad Universitaria, Mexico City, DF, 04510, Mexico

Keywords:
Malpighiaceae
Bunchosia
wood anatomy
bark anatomy
plant habit
evolution.

Presentation Type: Poster
Session: P, Anatomy and Morphology Posters
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 5:00 PM Time and date to be determined
Number: PAM010
Abstract ID:660
Candidate for Awards:Developmental and Structural Section best poster