Ferns: Past and present

From Past to Present: digitizing and visualizing ferns spanning 300 million years

History, Ecology and Culture

Pteridophytes (ferns and fern allies) were once a principal component of terrestrial ecosystems dating back 360 mya, dominating the Carboniferous landscape and are of great evolutionary significance. With over 10,000 known species, pteridophytes remain of great ecological significance and form the dominant and most conspicuous part of the vegetation in many ecosystems throughout the world. Ferns in general provide an ecological service as bio-indicators for habitat health because of their sensitivity and preference for temperature, humidity, soil type, moisture, pH, light levels, etc. Ferns thrive in a variety of habitats that flowering plants would often fail to dwell in such as tree limbs and rock crevices. Some are significant weeds and agricultural pests. The well known bracken fern (Pteridiumaquilinum (L.) Kuhn), produces arsenic-based compounds toxic to cattle and forms large aggressively spreading colonies. Ferns are widely used as ornamental plants and play an important role in many cultures throughout the world. The silver tree fern has been highly stylized for logos and trademarks and is used as an iconic symbol in New Zealand. Fiddleheads, the young frond which curls in a distinct design are edible, with a taste similar to asparagus. Pteridomania was a term coined in the mid 19th century during a time when Fern-Fever influenced a variety of Victorian aesthetic. The Phytologist was a popular publication often referenced by enthusiasts of the time. Many fancy forms were cultivated. After the mania faded early in the twentieth century, the number of kinds of fancy forms in cultivation dwindled; today some of them are known only from herbarium specimens (Lellinger, 1985 vii). Locally, the City of Chicago offers visitors botanical retreats at Garfield Park Conservatory and Lincoln Park Conservatory.

Structure

The fern body consists of 3 major parts-The fronds, the rhizomes and the sporangia. The rhizome is a horizontal-sometimes vertical- stem from which the fronds and roots grow. The frond is divided into two parts, the stipe (stalk) which grows from the rhizome and the blades (leaf). For fern allies, fronds are generally simple and are often small but ferns have a variety of complex designs with many veins and various divisions. The blades of the frond are distinguished from the leaves of a flowering plant because along with photosynthesis it also serves the purpose for reproduction with the presence of sori. Within the sori is a cluster of sporangia, spore-producing structures on the underside of the blades.  The fern propagates with the release of dust-like spores carried by the wind. This interactive explores the diversity of form in New Zealand ferns.

Classification

Extant ferns are currently being classified with the guidance of a paper that uses recent phylogenetic studies based on morphological and molecular data. (Smith, Pryer pdf)

Databasing and Digitizing Extant and Extinct Fern Collections

The significance of biological collections of museums and academic institutions is well documented (Graham et al. 2004; Berendsohn & Seltmann 2010) making countless contributions to science and society in general, environmental monitoring, and traditional taxonomy and systematics. Extensive, professionally managed natural history specimen collections, such as those at the Field Museum, embody the only comprehensive record documenting the fossilized and living members of the world’s ecosystems and their changes over time. We are currently at the height of unprecedented interest into the phylogenetic relationships among major groups of living and extinct plants.

We are currently in a pilot phase databasing and digitizing pteridophyte fossils from the Mazon Creek assemblage of Illinois (i.e. 315 mya) as well as extant fern specimens from the Great Lakes Region. This represents a novel and exciting inter-disciplinary initiative, offering an innovative synthesis of extinct and extant pteridophytes. The project will greatly increase the accessibility of the collections, making them available online to the scientific and broader community, with far reaching applications. The timing of the project is critical for its synergy with current strategic digitization and databasing efforts at FMNH, maximizing the utility of existing technical personnel, and amplifying current coordinated networks of collaborations that will benefit accelerated digitization for all partners. Five thousand fossil and extant pteridophyte specimens will be digitized, which will expand the already 400 digitized fern specimens from the Chicagoland area. Significantly, the project extends the engagement of students in collection-based programs with partnering universities and colleges in the Chicagoland area. This approach bridges the taxonomic endeavor, exposure to a world-class institution and its collections, and training with broader impact activities.

The Paleo-Botany Collection

In 2005, the Museum's Paleobotany Collections, which comprise over 90,000 cataloged specimens, moved into the newly opened Collections Resource Center (CRC), an on site facility that houses collections from Geology, Zoology and Anthropology. Within this facility, new compactor-mounted specimen cabinets and shelving have given Paleobotany a 135% increase in storage capacity.

Within FMNH, the recent core research drive has been to use the Palaeobotany Collections to develop and implement methods to determine changes in paleoclimate, paleoatmospheric composition and fire history (e.g. Glasspool and Scott, 2005; Brown et al., 2012). However, the Museum's Paleobotany Collections are a resource of international importance for systematic and evolutionary botany (e.g. Stull et al., 2012; Zhou et al., 2012; Spencer et al., 2013), for paleoecological / paleoclimatological research (e.g. Bacon et al., 2011) and as a paleobotanical teaching resource (Willis & McElwain, 2002) and over the last five years alone, new loans have been made of 5652 specimens to support this research. The FMNH Paleobotany Collections are continuously developing and over the last five years, total growth of cataloged specimens has measured 45.6%.

Succesful Pilot Phase

The pilot project is a joint collaboration between Ian Glasspool (Geology) and Matt von Konrat (Botany). Prior to the pilot phase, 500 fern type specimens were already scanned under the auspices of the Global Plant Initiative (GPI) with Mellon Foundation funding and 600 fern specimens were scanned under the vPlants initiative focusing on plants from the Chicagoland area. Following this, in preparation for the current proposal PI von Konrat and Co-PI Glasspool sought funding from the Grainger Foundation through funds administered by the Museum. A few achievements included but not limited to 466 fossil ferns and fern-allies imaged and added to EMu and encompass 62 genera and 144 species and an established taxonomy module for fern and lycopod classification, including some 2700 records for higher classification. This forms a baseline for fern collection management, curation and research. We now have in place nationwide, multi-institutional standards in the digitization of herbarium specimens. The Museum is also a hub for regional herbaria supported by the Mellon Foundation to digitize oversized specimens using a high-end camera. We propose to digitize the fossilized ferns based on experiences from that project and our own previous pilot project with strict standards and protocols in place.