A RE-EVALUATION OF THE JUNCUS TRIFORMIS COMPLEX (JUNCACEAE).
Item
-
Title
-
A RE-EVALUATION OF THE JUNCUS TRIFORMIS COMPLEX (JUNCACEAE).
-
Identifier
-
AAI8319763
-
identifier
-
8319763
-
Creator
-
ERTTER, BARBARA JEAN.
-
Contributor
-
Arthur Cronquist
-
Date
-
1983
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Biology, Botany
-
Abstract
-
The Juncus triformis complex is a small group of dwarf annual rushes in western North America. All have narrow basal leaves, inconspicuous bracts, solitary terminal heads or flowers, 2-3 stamens, and completely plurilocular capsules. The complex illustrates a progressive adaptation to seasonally moist habitats, involving development of an annual habit, reduction in size of plant to only 2 cm, reduction in number of flowers to only 1, loss of bracts and inner stamens, transition from trimery to dimery, and transition from out-crossing to selfing as the primary mode of pollination. Chromosome numbers display an aneuploid reduction series from n = 19 to n = 16.;The complex was last revised in 1948 by Hermann, who recognized nine species. The present revision recognizes nine species and two additional varieties, a total of 11 taxa, arranged into four informal groups. Changes from Hermann's revision are the segregation of two new species (J. luciensis and J. tiehmii) from J. kelloggii, the discovery of a new variety (J. leiospermus var. ahartii), the reduction of J. abjectus to a variety of J. hemiendytus, and the inclusion of J. megaspermus within J. triformis.;A combination of scanning electron microscopy of seed coat patterns and morphological data indicate that the closest relatives of the J. triformis complex are either a group of Southern Hemisphere perennials, the New World perennials J. marginatus and J. filipendulus, or the South African annuals, all in subg. Graminifolii. The association of the J. triformis complex with the South African annuals and J. capitatus as a segregate subg. Juncinella is rejected.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
-
Program
-
Biology
