Abstract Detail

Developmental and Structural Section

Griffith, M. Patrick [1], Tomlinson, P. [2], Stevenson, Dennis [3], Vovides, Andrew [4], Meerow, Alan [5], Francisco-Ortega, Javier [6], Calonje, Michael [1], Magellan, Tracy [1].

Structural evolution of cycads: Do traits in extant cycads inform ancestral conditions?

Cycads are often used as models for early evolution of plant structure. One long-held hypothesis is that cycads inform early seed plant biology. Recent phylogenetic work can help inform such hypotheses. An emerging finding offers a new context: while major lineages diverged in the Mesozoic or before, modern cycad species are of very recent origin. So, given the modernity of extant cycad diversity, are extant structural characters useful for interpreting early cycad evolution? If modern anatomy is very divergent, and divergent from early cycads, polarity of these traits may inform structural evolution. Testing phylogenetic resolution of modern cycad structure by reciprocal illumination and other techniques can help clarify the use of cycads as living models of ancient plant biology. We examine three basic questions:(1) What is the range of anatomical variation in extant cycads? (2) How useful is anatomy in cycad systematics? (3) What phylogenetic signals can be understood from anatomical characters? Structural characters studied emphasize leaflets, based largely on fresh material collected from the living collections at Montgomery Botanical Center, and Jardin Botanico Francisco Clavijero, and also on characters from fossil cycads. Current results are presented as a synoptic key to genera, which gives some indication of present diversity. Further work will surely refine this information.

Broader Impacts:

1 - Montgomery Botanical Center, 11901 Old Cutler Road, Miami, FL, 33156, USA
2 - 54 Floret Circle, Hinsham, MA, 02043, USA
3 - THE NY BOTANICAL GARDEN, 2900 SOUTHERN BLVD, BRONX, NY, 10458-5126, USA, 718/817-8632
4 - INSTITUTO DE ECOLOGIA AC, APDO POSTAL 63, XALAPA, VER, 91000, México
5 - USDA-ARS-SHRS, UNITED STATES DEPARTMENT OF AGRICULTURE, 13601 Old Cutler Road, Miami, FL, 33158, USA
6 - Florida International University & Fairchild Tropical Botanic Garden, Miami, FL, 33199, USA

Keywords:
cycads
biological research collections
Anatomy
Cycadales
Zamiaceae
Cycadaceae.

Presentation Type: Oral Paper:Papers for Sections
Session: 40
Location: Union D/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:45 PM
Number: 40006
Abstract ID:286