Abstract Detail

Floristics & Taxonomy

Calvillo-Canadell, Laura [1], Daly, Douglas C. [2], Mitchell, John Dan [3].

Using herbarium specimens to carry out comparative foliar morphological studies: Foliar architecture of Anacardiaceae and Burseraceae.

Herbaria house scientific collections of dehydrated plant specimens from various parts of the world. These places are essential to conserve the world’s biodiversity and to provide basic information to carry out botanical research. In most taxonomic studies, the identification and classification of plants is based mainly on reproductive characters, but vegetative characters are also important and useful. Here we present advances of a research project that employs herbarium leaves to study foliar architecture as a tool to a better understanding the taxonomy and systematics of two highly diverse sister families of angiosperms: Burseraceae and Anacardiaceae. Within this main objective, we want to determine if there is morphological variation between species, to distinguish patterns in and between families, and to discover new taxonomically characters that can be tested in future phylogenetic studies. To do this, we generated a morphological matrix that includes 77 foliar characters, like shape and symmetry of the blade, type of margin, shape of the base and apex, order and course of venation, presence of areoles, type of teeth. After requesting permission, leaf samples were taken from specimens of different herbaria and subjected to a clearing and staining protocol to facilitate the observation of the leaf architectural characters. Cleared and stained leaves were photographed and scanned. Currently 260 leaves from 119 species have been processed and coded. We found that in both families the primary venation is pinnate, the secondary veins can be brochidodromous, semi-crapedodromous or cladodromous, and that the fourth and fifth vein orders can be reticular, freely branched, or opposite percurrent. Most species have leaves with a fimbrial vein, and the last marginal venation may be incomplete or rarely complete. Most species present leaves with entire margins, but some can be dentate or serrated. Certain leaf architectural characters can distinguish genera within each family, for example most leaves of the the genus Bursera (Burseraceae) have elliptical and symmetric laminas, secondary framework feestoned brochidodromous venation, secondary spacing in middle irregular, epimedial tertiaries, tertiary fabric alternate percurrent and irregular reticulate. On the other hand, leaves of the genus Spondias (Anacardiaceae) present constant characters such as craspedodromous secondary framework and irregular-reticulate and freely ramified tertiary venation. Our dataset will be the most comprehensive foliar architectural dataset for Anacardiaceae and Burseraceae and will provide insight into the leaf architecture evolution of both families.

1 - Instituto De Biología, Universidad Nacional Autónoma De México, Botany, 3er Circuito Exterior, Ciudad Universitaria, Coyoacán., Ciudad De México, DIF, 04510, Mexico
2 - Institute of Systematic Botany., New York Botanical Garden, 2900 Southern Blvd., Bronx, New York 10458, Bronx, NY, 10458
3 - New York Botanical Garden, Institute Of Systematic Botany, 2900 Southern Blvd, Bronx, NY, 10458, United States

Keywords:
Anacardiaceae
Burseraceae
Leaf Architecture
Bursera
herbarium
morphology.

Presentation Type: Oral Paper
Session: FTIII, Floristics & Taxonomy III
Location: Virtual/Virtual
Date: Friday, July 23rd, 2021
Time: 12:30 PM(EDT)
Number: FTIII001
Abstract ID:845
Candidate for Awards:None