Lambertiflora elegans E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, 2020

Friis, Else Marie, Crane, Peter R. & Pedersen, Kaj Raunsgaard, 2020, Multiparted, Apocarpous Flowers From The Early Cretaceous Of Eastern North America And Portugal, Fossil Imprint 76 (2), pp. 279-296 : 283-286

Lambertiflora elegans E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN sp. nov.

Text-figs 3a–e , 4a–c

H o l o t y p e. Designated here. PP53796 (Puddledock sample 082; figured Text-figs 3a–e , 4a–c ).

P l a n t F o s s i l N a m e s R e g i s t r y N u m b e r.

PFN000905 (for new species).

R e p o s i t o r y. Paleobotanical Collections, Department of Geology, Field Museum, Chicago, Illinois, USA (PP).

E t y m o l o g y. From the slender, elegant shape of the fossil.

T y p e l o c a l i t y. Puddledock , former Tarmac Lone Star Industries (Vulcan Materials) sand and gravel pit, located south of Richmond and east of the Appomattox River in Prince George County, Virginia, USA (37° 15′ 52″ N, 77° 22′ 10″ W) .

T y p e s t r a t u m a n d a g e. Basal part of Subzone IIB, Potomac Group; Early Cretaceous (early to middle Albian).

D i a g n o s i s. As for the genus.

D i m e n s i o n s. Length of flower bud (stalk excluded):

1.3 mm; diameter: 0.75 mm.

D e s c r i p t i o n a n d r e m a r k s.Thespeciesisbased on a single, charcoalified, three-dimensionally preserved flower bud ( Text-figs 3a–e , 4a–c ). The bud is borne on a long slender pedicel ( Text-fig. 3a ) and was probably solitary. It is preserved at an early developmental stage and charcoalification has also caused many of the cell walls to burst. As a result details of the androecium and gynoecium are not clear ( Text-figs 3c–e , 4a–c ).

The perianth is the best preserved part of the flower bud. It consists of about 30 narrowly elongate tepals with rhomboidal bases ( Text-figs 3a–e , 4a–c ). Tepals are undifferentiated and arranged spirally, in several series. The androecium consists of many parts, but the early developmental stage at which the flower bud was preserved, together with the nature of the preservation, precludes establishing the precise number of stamens and their arrangement ( Text-figs 3c–e , 4a–c ). For the same reason, information on anthers and dehiscence mode is also lacking. The gynoecium appears to be preserved only as crowded poorly developed carpels (possible carpel primordia) on the conical receptacle ( Text-figs 3d, e , 4a, b ).

All tissues of the floral bud contain a number of larger, rounded cells that are probably secretory. These are densely spaced inside the tissues of the floral bud and are also seen on the surface of the tepals and pedicel where the cells have burst open ( Text-figs 3d, e , 4a–c ).

Figures

Text-fig. 3. Scanning electron micrographs (a, b) and synchrotron radiation X-ray tomographic microscopy orthoslices (c–e) of flower of Lambertiflora elegans gen. et sp. nov. from the Early Cretaceous Puddledock locality, Virginia, USA (holotype, PP53796, Puddledock sample 082). a) Flower in lateral view showing long pedicel and overlapping elongated tepals; b) Detail of flower showing overlapping elongated tepals; note the numerous holes indicating the position of probable secretory cells; c) Flower in longitudinal section showing overlapping elongated tepals, remains of probable poorly developed stamens or staminodes and probable poorly developed carpels on the central conical gynoecial region of the receptacle (cut between orthoslices xz0510 and 0570); d) Flower in longitudinal section (comparable to c) showing overlapping tepals, poorly developed stamens or staminodes, and probable poorly developed carpels on the central conical gynoecial region of the receptacle; note the prominent cavities from secretory cells scattered through the tissues (cut between orthoslice xz0560 and 0575); e) Flower in transverse section showing overlapping tepals, poorly developed stamens or staminodes, and remains of probable poorly developed carpels (cut between orthoslices xy1160 and 1180). Scale bars = 1 mm (a), 500 µm (b–e).

Text-fig. 4. Synchrotron radiation X-ray tomographic microscopy orthoslices of flowers of Lambertiflora virginiense gen. et sp. nov. from the Early Cretaceous Puddledock locality, Virginia, USA (holotype, PP53796, Puddledock sample 081). White dots – tepals, yellow dots – stamens or staminodes, red dot – central conical gynoecial region. a) Flower in longitudinal section showing elongated overlapping tepals, remains of probable poorly developed stamens or staminodes and probable poorly developed carpels on the central conical gynoecial region of the receptacle (orthoslice yz0454); b) Flower in transverse section showing rhomboidal bases of 30 tepals, nine poorly developed stamens or staminodes, and the central poorly differentiated gynoecial region of the receptacle (orthoslice xy1160); c) Flower in transverse section at the level of the floral receptacle showing 30 tepals, nine of the poorly developed stamens or staminodes, and the central poorly differentiated gynoecial region of the receptacle (orthoslice xy1250). Scale bars = 250 µm (a–c).