2 小时之前 · The extinction of Gigantopteris plants in South China and across the ancient supercontinent ... Tree trunks and fern stems ... They used detailed analysis of fossil pollen and spores and a new ...

2022年5月27日 · Plants have produced pollen for hundreds of millions of years, investing great amounts of energy into dispersing the reproductive material far and wide. Despite their tiny size, pollen grains...

Plants have evolved numerous ways for pollen to make contact with ovules. The most ancient plants (fern-like plants 300 million years ago) relied on wind pollination, and modern conifers and grasses still do. Some conifers have adaptations to increase the chances that wind-scattered pollen reaches its target.

Saccate pollen is present in many ancient seed plants and in two families of extant conifers. In living conifers, saccate pollen occurs in taxa that combine erect ovulate cones at the time of pollination, inverted ovules, and pollination drops. Sacci function primarily to float pollen grains through a liquid pollination drop and concentrate ...

The question arises why so many plant propagules (especially fern and moss spores, pollen grains) have usually sporopollenin within their outermost wall layers. The (probably) simple answer is that the “invention” and production of sporopollenin was a prerequisite for becoming a land plant in the Silurian.

2023年9月1日 · The study includes a late Permian lyginopterid seed fern from Jordan and a Middle Jurassic conifer from Siberia. Several reasons could account for such “in situ only” pollen types, including the scarcity of the parent plants, low pollen productivity, entomophily, or immaturity of in situ pollen, although the last variant seems overestimated ...

True ferns (the plants we know most commonly as “ferns”) are an extremely diverse group of vascular plants that first appear in the fossil record during the Devonian period (380 million years ago). However, many of the species we know today did not appear until the Cretaceous period (145 million years ago), when a major radiation occurred.

2009年4月23日 · These ancient spores and pollen show up in the fossil record between 465 million and 407 million years ago, a key moment for Earth’s greenery. During the first half of that period, the nonvascular land plants—mosses, liverworts, and hornworts—held sway, dominating the landscape for 30 million years.

2012年1月1日 · Spores from club mosses (e.g., Lycopodium), spike mosses (e.g., Selaginella), bracken ferns (Pteridium), and polypody ferns (Polypodium) are among those found in archaeological materials.

Until about 200 million years ago, there were no flowering plants. Ferns, cycads and conifers dominated the earth. Then at the end of the Jurassic Period the first flowers evolved, creating the greatest change the world has ever seen. For the first time, plants provided animals with nectar, pollen and fruit to eat.