Hedyflora crystallifera E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, 2019

Friis, Else Marie, Crane, Peter R., Pedersen, Kaj Raunsgaard, Mendes, Mário Miguel & Kvaček, Jiří, 2022, The Early Cretaceous Mesofossil Flora Of Catefica, Portugal: Angiosperms, Fossil Imprint 78 (2), pp. 341-424 : 351-353

Hedyflora crystallifera E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, 2019

Text-fig. 7a–f

D e s c r i p t i o n a n d r e m a r k s. Hedyflora crystallifera was established based on floral structures with adhering pollen from the Buarcos mesofossil flora ( Friis et al. 2019b). The specimens from Catefica are often strongly compressed and lignitised. Internal details are known from only a few specimens. It is possible that the material represents more than one species, but the information currently available does not warrant recognition of several taxa. Differences in size may be attributed to differences in maturity as the floral structures appear to be preserved at different post-anthetic stages. The fruits/ovaries are obovate in longitudinal view, triangular in transverse section with rounded to sharp edges ( Text-fig. 7a, b, d ), and have the remains of three apical tepals ( Text-fig. 7a, b ). The hypanthium is thickened over the edges of the fruits with lateral depressions between the angles ( Text-fig. 7a, b ). The outer surface of the hypanthium over the lateral depressions shows polygonal cells each with a central papilla ( Text-fig. 7c ).

Fruits of Hedyflora are one-seeded with an orthotropous, pendent and endotestal seed. The endotesta is distinctly crystalliferous and the outer tegmen is sclerified ( Text-fig. 7d ).

Pollen grains attached to the surface of several fruits are circular in equatorial view, about 22 µm in diameter, and have an irregular branched polar aperture. The aperture is typically tetrachotomocolpate with a poorly defined aperture membrane that has irregular verrucate ornamentation ( Text-fig. 7e ). The tectum is reticulate with narrow muri, about 0.3 µm wide, ornamented by two poorly defined rows of minute verrucae and supported by long, scattered columellae ( Text-fig. 7f ).

A f f i n i t y a n d o t h e r o c c u r r e n c e s. Hedyflora is closely similar to the pistillate flowers and fruits of extant Hedyosmum SW. (Chloranthaceae) from which it is mainly distinguished by the more elaborate seed coat in the fossil material. Extant Hedyosmum has an unspecialized seed coat that lacks a crystalliferous endotesta and also lacks sclerified cells in the tegmen, both features that are shared by Hedyflora and other extinct and extant Chloranthaceae ( Friis et al. 2019b) . Fossils assigned to Hedyflora are known from several mesofossil floras from Portugal, including Arazede, Buarcos, Torres Vedras and Vale de Água ( Friis et al. 2019a, b). Pollen grains are similar to dispersed fossil grains typically assigned to the pollen genus Asteropollis R.W.HEDL. et G.NORRIS. Closely similar grains are also found in situ in an isolated stamen from Catefica (“Stamen with Asteropollis - type pollen sp. 1”; Text-fig. 14 ) and similar grains also occur in situ in stamens from the Vale de Água locality ( Friis et al. 2019b). Dispersed pollen grains of the Hedyflora type are also present in the Catefica palynoflora, but are rare.

Figures

Text-fig. 7. Scanning electron microscope (SEM, a–c, e, f) and synchrotron radiation X-ray tomographic microscopy (SRXTM, d) images of fruits and pollen grains of Hedyflora crystallifera; Catefica locality, Portugal. a, b) Lateral view of fruits showing the remains of apical tepals and remains of the hypanthium, which is thicker on the edges of the fruit in (b) (arrows); c) Detail of hypanthium surface between the thickenings on the edges of the fruit showing polygonal cells with a central papilla; d) Transverse section (orthoslice xy0600) of fruit and seed showing the finely crystalliferous endotesta (arrowhead) and sclerified outer tegmen (asterisk); e) Distal view of pollen grain from surface of fruit showing the poorly defined tetrachotomocolpate aperture (daggers indicating the four arms of the aperture) and semi-tectate, reticulate tectum; f) Detail of pollen wall showing narrow muri with indistinctly beaded surface ornamentation of minute verrucae in poorly defined rows and supported by long columellae. Specimens, Catefica 49-S172313 (a), Catefica 49-S153159 (b), Catefica 49-S172324 (c), Catefica 49-S172325 (d), Catefica 50-S170453 (e, f). Scale bars = 300 Μm (a, b), 100 Μm (d), 50 Μm (c), 6 Μm (e), 1.5 Μm (f).

Text-fig. 14. Scanning electron microscope (SEM) images of “Stamen with Asteropollis-type pollen sp. 1”; Catefica locality, Portugal. a) Stamen with pollen in situ; b–d) Pollen in situ in stamen in (a) showing poorly defined tetrachotomocolpate aperture and semitectate-reticulate tectum; e) Detail of pollen wall showing semitectate-reticulate tectum with long, scattered columellae supporting the narrow muri; note two irregular rows of minute verrucae ornamenting surface of muri. Specimen, Catefica 50- S170385 (a–e). Scale bars = 600 Μm (a), 20 Μm (b), 6 Μm (c, d), 1.5 Μm (e).