Miranthus E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, 2021

Friis, Else Marie, Crane, Peter R. & Pedersen, Kaj Raunsgaard, 2021, Early Flowers Of Primuloid Ericales From The Late Cretaceous Of Portugal And Their Ecological And Phytogeographic Implications, Fossil Imprint 77 (2), pp. 214-230 : 216

Genus Miranthus E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN gen. nov.

T y p e. Miranthus elegans E.M.FRIIS, P.R.CRANE et

K.R.PEDERSEN gen. et sp. nov.

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.

PFN002665 (for new genus).

E t y m o l o g y. From the village of Mira close to where the fossils were collected.

D i a g n o s i s. Flowers pedicellate, structurally bisexual, actinomorphic, pentamerous and isomerous. No bracteoles present immediately under calyx. Sepals narrowly triangular, basally fused, persistent. Petals ovate, longer than sepals. Stamens opposite corolla lobes; staminodes alternating with the corolla lobes. Ovary semi-inferior, unilocular, of five carpels; single style long with a wide stylar canal that is five-angled in cross-section. Apical portion of ovary with a slightly raised nectariferous ring and stomata-like openings. Placentation free, central. Ovules numerous and densely spaced on the placenta, but not immersed. Ovules anatropous and bitegmic. Fruit a capsule. Seeds many, minute, angular, with reticulate surface.

C o m m e n t s o n t h e g e n u s. The combination of distinctive floral features clearly places Miranthus in the Primulaceae s. l. and all features recorded for the fossil material are known also for the extant primuloid genus Samolus L. (subfamily Theophrastoideae ). However, Miranthus also closely resembles flowers of other members of the subfamily, and because not all floral features of the fossil taxon are sufficiently well-known we refrain from assigning the fossils to an extant genus.

To our knowledge there are no comparable flowers recorded from the fossil record. Three possible primuloid flowers from the Cainozoic Baltic amber, Berendtia primuloides GÖPP. , B. rotata CONW. and Myrsinopsis succinea CONW. are fragmentary, and are preserved only as dispersed, sympetalous corollas with attached stamens ( Göppert and Berendt 1845, Conwentz 1886).