Weltrichia is a genus belonging to the extinct seed plant group Bennettitales. It is a form genus representing flower-like male pollen-producing organs. It is associated with the female ovulate cone Williamsonia.
Description
Diagram of Weltrichia givulescui. Labels: CFR Centrifugal ray; CPR Centripetal ray; MR Median ridge; FS Fibrous strand; PS Pollen sac position (in this case, pollen sac attachment); CC Central cup; RBA Resin (resinous) body or attractant; ST Stalk
Although the morphology of Weltrichia is highly variable, the overall morphology consists of a central cup-like structure surrounded by a number of radially symmetrical outward projecting rays, to which are attached bivalve-shaped pollen sacs/synangia. The number of rays varies from 9/10 to 30, depending on the species, and the total diameter from 3 centimetres (1.2 in) to over 20 centimetres (7.9 in). Both the cup and rays usually (but not always) have substantial thickness, in some of the thicker species the structure is noticeably woody. The pollen is monocolpate and elliptical. In some species, additional rays project over the central cup, and attractants/resinous substances are present within the cup. The rays also sometimes have ridges, trichomes, appendages, striae and/or unipinnate (pedicellate) pollen sacs present. Species of Weltrichia appear to have primarily been wind pollinated, though some species may have been pollinated by insects, such as beetles. They were borne by the same plants that also bore female ovulate cones assigned to Williamsonia.[1] It is unclear whether the parent plants were monoecious (having both structures on one plant) or dioecious (where each plant only has one gender of reproductive organ). At least some bearers of Weltrichia, such as Kimuriella from the Late Jurassic of Japan were low growing divaricately branching shrubs with a maximum height of 2–3 metres, while others such as Williamsonia gigas may have been more cycad-like in morphology.[2]
Distribution
Weltrichia is known from Asia, Europe, and North America, as well as India (which formed part of the separate landmass Gondwana at the time), spanning from the Late Triassic to the Late Jurassic/Early Cretaceous.[1]
About 100 mm in diameter, with only 9/10 rays, has the lowest number of rays of any species
Weltrichia ayuquiliana
Mexico
Middle Jurassic
Around 60 mm in diameter
Weltrichia daohugouensis
China
Middle Jurassic
Around 100 mm in diameter
Weltrichia fabrei
France
Late Triassic-Early Jurassic
Only known from fragmentary remains
Weltrichia givulescui
Romania
Early Jurassic (Sinemurian)
Maximum of 100 mm in diameter
Weltrichia harrisiana
India
Middle Jurassic
Approximately 120–150 mm in diameter
Weltrichia hirsuta
Iran
Early Jurassic
Approximately 130–140 mm in diameter
Weltrichia huangbanjingouensis
China
Late Jurassic/Early Cretaceous
Only central cup is preserved
Weltrichia johannae
Romania
Early Jurassic (Sinemurian)
70 mm in diameter
Weltrichia maldaensis
India
Late Jurassic
70 mm in diameter
Weltrichia microdigitata
Mexico
Middle Jurassic
Diameter of only 30 mm, making it smallest known species
Weltrichia mirabilis (type)
Germany
Early Jurassic
Approximately 100 mm in diameter
Weltrichia mixtequensis
Mexico
Middle Jurassic
Diameter of 160 mm
Weltrichia oolithica
Italy
Late Jurassic
70–80 mm in diameter, holotype specimen currently unlocated
Weltrichia pecten
England
Middle Jurassic
Typically 100–120 mm in diameter. Has been suggested to be synonymous with Weltrichia spectabilis and Weltrichia whitbiensis.[2]
Weltrichia primaeva
Iran
Early Jurassic
Only known from large (over 60 mm in length) ray fragments with a complex morphology
Weltrichia santalensis
India
Middle-Late Jurassic
With a diameter of 220–230 mm, it is one of the largest species in the genus
Weltrichia setosa
England
Middle Jurassic
Typically 120 mm in diameter.
Weltrichia sol
England
Middle Jurassic
One of the largest species, at 170–200 mm in diameter, associated with the female cone Williamsonia gigas and the leaves Zamites gigas
Weltrichia spectabilis
England
Middle Jurassic
Central cup 40 mm in diameter and rays 30-50 mm in length, which bear apical filiform whiskers, which can reach 30-60 mm in length.[1] Has been suggested to be synonymous with Weltrichia pecten and Weltrichia whitbiensis.[2]
Weltrichia steierdorfensis
Romania
Early Jurassic (Sinemurian)
Around 105–120 mm in diameter
Weltrichia whitbiensis
England
Middle Jurassic
Around 120–130 mm in diameter.[1] Has been suggested to be synonymous with Weltrichia pecten and Weltrichia spectabilis.[2]
