Mashayekhi, Saeideh , Columbus, J. Travis .
Leaf anatomy of Allium (Alliaceae) in North America.
The genus Allium (Alliaceae) is distributed over mid-latitude regions from the dry subtropics to the boreal zone. It includes ca. 750 species total, with ca. 86 species in North America. The main center of diversity extends from the Mediterranean Basin to central Asia and Pakistan. A second center of diversity occurs in western North America. Thirteen subgenera are recognized. Subgenus Amerallium is divided into two clades: New World and Old World. Most of the New World species are in subgen. Amerallium and occur in California (ca. 50 species) and Texas (ca. 14 species). New World species have been placed into eight alliances based on morphological similarities. Characteristics of subgen. Amerallium include one-nerved tepals, one row of vascular bundles in the leaf, absence of leaf palisade parenchyma (if present, secondarily evolved from spongy mesophyll), and the presence of subepidermal leaf laticifers. Thus far we have sampled 50 New World species for transectional leaf anatomy. Permanent slides of sections from the middle of the blade were examined. The sections reveal a surprising amount of variation in both round and flat leaves in terms of arrangement of mesophyll cells, laticifer cells, and vascular bundles. Despite reports of one row of vascular bundles in subgen. Amerallium, we found two rows of vascular bundles in some species. A separate ongoing study involves the molecular phylogenetics of New World Allium. The anatomical variants of the leaves will be discussed in context of the phylogeny.
Log in to add this item to your schedule
1 - Rancho Santa Ana Botanic Garden, Botany, 1500 N. College Ave., Claremont, CA, 91711, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 555A/Convention Center
Date: Monday, August 2nd, 2010
Time: 9:30 AM