Among the most important finds that belonged to De Zigno’s collection are the Lower Jurassic fossil plants coming from the Grey Limestones, both on the Monti Lessini and on the Asiago Plateau.

Such fossil flora was one of De Zigno’s main subject of study throughout his life. De Zigno published a few works in this field, until he arrived at the important monograph Flora Fossilis Formationis Oolithicae, first published in different issues. De Zigno presented the results of his researches in a very skillful way. The work was a huge endeavour, however, De Zigno received the golden medal of Società Italiana delle Scienze dei XL for its completeness and iconographic beauty. The study and research on Jurassic fossil plants was a subject that De Zigno had carried out from 1849 to the year of his death, even if in an intermittent way, often comparing the Italian fossil flora with the British flora of the ‘Great Oolite’ (Middle Jurassic).

Otozamites sp. (MGP-PD 4137)
Cycad leaf
Origin: Val d'Assa (Vicenza)
Period: Lower Jurassic

Dichopteris visianica

This plant, originally presented by De Zigno as a fern, actually belongs to the Pteridospermae, a group of plants whose seeds are extinct today. The specific name of that plant is dedicated to the Prefect of Padua Botanical Garden, Roberto De Visiani (1800-1878).

The find belonging to the De Zigno collection is kept in the section of Geology and Paleontology of the Museum of Nature and Humankind of the University of Padua. That find has been commented and reproduced in plate XII of: De Zigno, A. (1865). Monografia del genere Dichopteris. Memorie dell'I. R. Istituto veneto di scienze, lettere ed arti, 12, [211]-225, 3 tavv.

The same fossil plant had been depicted in a draft that nowadays is kept with the preparatory materials for the unpublished work by Achille De Zigno Fossiles de la Vénétie at the Geosciences Library of the University of Padua.

The fossil flora of Recoaro

Abramo Massalongo (1824-1860) was the first scholar to gather a systematic collection of fossil plants found in the stratigraphic succession the area of Recoaro, Vicenza. His premature death prevented him from completing his research. De Zigno collected the scientific inheritance of his friend and associate, and in 1862 published the monograph ‘Sulle piante fossili del Trias di Recoaro raccolte dal Prof. A. Massalongo’. The work established numerous new species. The more important and more abundant taxon from this area was without any doubt Voltzia recubariensis of which leaves, reproductive organs and fossil resin are known.

In Massalongo and De Zigno’s time, in the area around Recoaro were recognised 2 distinct fossil plants horizons, both attributed to the Triassic. Only later, researchers were able to assign the lower horizon to Upper Permian (the sandstones of Val Gardena) and the upper horizon to the Middle Triassic ('Strati a Voltzia', Anisian).

Today both floral associations need a ‘modern’ systematic revision.

The collection of fossil plants from Recoaro originally studied by De Zigno is now kept in the Hall of Palms, in the section of Geology and Palaeontology of the Museum of Nature and Humankind of the University of Padua (MNU).