The information in this database includes species identity, genus and family of each species, and their elevational distribution range and plant groups (overall plants, seed plants, bryophytes, and ferns).
More than half of these species were seed plants (80.3%, 116 families, 524 genera, and 1491 species), while the number of bryophytes (48 families, 117 genera, and 257 species) and ferns (21 families, 40 genera, and 110 species) accounts for 13.8% and 5.9%, respectively (Table 1).
doubt, widespread zooidogamy among ancient seed plants. Although the
1951), which is on the stem lineage of the extant seed plants (Nixon et
"Our work has shown that oleanane is lacking from a wide range of fossil plants," he notes, "but the chemical is found in Permian sediments containing extinct seed plants called gigantopterids."
That makes gigantopterids the oldest oleanane-producing seed plants on record--an indication that they were among the earliest relatives of flowering plants, concludes biologist David Winship Taylor of Indiana University Southeast, New Albany, a co-author of the study.
Farmers from states like Morelos, Hidalgo, Aguascalientes and San Luis Potosi have made pilgrimages to Milpa Alta and taken home seed plants
that provided the basis for their own fields.
Almost all of the more than 250,000 extant species of seed plants
engage in a complex life cycle that alternates between two organismal generations, the sporophyte and the unisexual male and female gametophytes.
The series presents every group of plants that grow in Illinois from algae and fungi through seed plants
, and this is the third volume on dicotyledonous plants.
It presents identification keys to more than 4,200 taxa of pteridophytes and seed plants
that are native or naturalized in Florida.
Endozoochory is common for seed plants
, but its usefulness for other taxa is largely unknown.
The newly found fossil might represent the first evidence of an intermediate stage between pteriodphytes and early seed plants
. Alternatively, it may have served a primitive gymnosperm that later gave rise to a subgroup of today's gymnosperms, Galtier says.