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SYSTEMATIC SIGNIFICANCE OF SEED‐SURFACE FEATURES IN ORTHOCARPUS (SCROPHULARIACEAE—SUBTRIBE CASTILLEJINAE)
Author(s) -
Chuang T. I.,
Heckard L. R.
Publication year - 1983
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1983.tb06426.x
Subject(s) - biology , coat , hilum (anatomy) , scrophulariaceae , botany , synapomorphy , key (lock) , type (biology) , monophyly , lineage (genetic) , anatomy , phylogenetics , paleontology , clade , biochemistry , ecology , gene
Scanning electron microscope and light microscope examination of seed‐coat features of 26 species of Orthocarpus have allowed recognition of many species‐level differences (summarized in a key) and of three seed‐coat types that parallel taxonomic subgroups but support realignments at generic and infrageneric levels. Type 1 seeds (subg. Orthocarpus , sect. Orthocarpus ) have a lateral hilum, sculptured inner tangential seed‐coat walls, and a tightly fitting outer seed coat. They are very similar to seeds of Cordylanthus . Seeds of Types 2 and 3 have a terminal hilum and membranous inner tangential cell walls. Type 2 seeds (subg. Orthocarpus , sects. Castillejoides and Cordylanthoides , with one exception) have a net‐like, loosely fitting outer seed coat that shows close relationship to seeds of Castilleja . Inner tangential walls of Type 2 seeds normally rupture. Type 3 seeds (subg. Triphysaria , with two exceptions) have a tightly fitting outer seed coat and inner tangential walls are always retained. Seed features support evidence from floral morphology and chromosome numbers that Orthocarpus as currently recognized is not a monophyletic lineage.