Dr. De-Ming Wang from Peking University and colleagues have described a new early seed plant from the Devonian of China. The earliest known ovules in the
Late Devonian (Famennian) are borne terminally on fertile branches and are
typically enclosed in a special branched system, called a cupule. Among these ovules are some that have terete
integumentary lobes with little or no fusion.
Wang et al report a new taxon, Latisemenia longshania, from the Famennian of South China, which bears cupulate
ovules that are terminal as well as opposite on the fertile axis. Each ovule has
four broad integumentary lobes, which are extensively fused to each other
and also to the nucellus. The cupule has only one ovule, and the five flattened
cupule segments of each terminal ovule are elongate, wedge-shaped, and shorter
than the ovule.
Associated, but not attached pinnules are laminate and Sphenopteris-like, with an entire or lobed margin.
Latisemenia is the earliest known plant with
ovules borne on the side of the fertile axis and may foreshadow the
diverse ovule arrangements found among younger seed plant lineages
that emerge in the Carboniferous. Following the Telome Concept, Latisemenia demonstrates derived features in
both ovules and cupules, and the shape and
fusion of integumentary lobes suggest effective pollination and protection
to the nucellus. Along with other recent discoveries from China, Latisemenia extends the palaeogeographic range
of the earliest seed plants.
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