Collecting in situ/adhered pollen from fossil compressed angiosperm flowers

Abstract

Fossilised compressed angiosperm flowers that can be determined in a botanically/systematically meaningful sense are rare in the fossil record. The main reason for this might be the preservation state, i.e., such fossils are in many cases strongly compacted, and can lack diagnostic features essential for proper identification and assignment to extant or (natural) extinct taxa. Since pollen morphology can be very conservative and of diagnostic significance at family and/or genus level from the Upper Cretaceous to modern times, analysis of in situ pollen is a crucial tool in identifying flowers. Unfortunately, despite its potential taxonomic value already addressed nearly 200 years ago by Heinrich Göppert, fossil in situ pollen from compressed flowers has not yet become a “standard” research subject in modern-day palaeobotany. Possible reasons for this may be due to the effort and complexity related to the detection and extraction of said in situ pollen. The method described herein fills this gap and makes it easy for everyone (students and professionals) to screen flower compression fossils and to extract in situ or adhered pollen from the flowers. It also provides a fast and practical way to process fossil pollen prior to photography with light- and scanning electron microscopy for future taxonomic work.