Abstract Detail

Systematics Section/ASPT

Ickert-Bond, Stefanie [1], Gerrath, Jean [2], Posluszny, Usher [3], Wen, Jun [4].

Inflorescence development in the Vitis–Ampelocissus clade of Vitaceae: The lamellate inflorescence of Pterisanthes confirms the Ampelocissus bauplan.

Pterisanthes (Vitaceae) is a genus of ca. 20 species of scandent climbers endemic to Southeast Asia with unusual lamellate inflorescences. Recent phylogenetic studies have shown that Pterisanthes, Nothocissus, Ampelocissus and Vitis form the well-supported Vitis-Ampelocissus clade. However, of these, inflorescence morphology has only been studied in depth in Vitis. We documented inflorescence development from initiation to maturation in Pterisanthes eriopoda, which has allowed us to understand the origin of this unusual lamellate inflorescence and its relationship to other vitaceous inflorescences. Floral material of different developmental stages from P. eriopoda was studied using epi-illumination microscopy, light microscopy and scanning electron microscopy. As in Vitis and Ampelocissus, the first-order branches in P. eriopoda develop helically around the inflorescence axis. This pattern is restricted to the Vitis-Ampelocissus clade in Vitaceae. In Vitis and most species of Ampelocissus, the inflorescence is a thyrse because subsequent branching orders culminate in the typical vitaceous determinate dichasium. In some species of Ampelocisssus (Ampelocissus sects. Kalocissus (Miq.) Planch. and Ridleya Latiff) and Pterisanthes eriopoda, however, inflorescence branching is restricted to the first order. Subsequent lateral growth of the first-order branches combined with the inhibition of peduncle or pedicel formation and loss of dichasial branching results in the unique lamellae, on which the flower primordia arise directly in a helical pattern. Given the recent phylogenetic results that placed Pterisanthes firmly within Ampelocissus, the most likely scenario is that the specialized Pterisanthes inflorescence is derived from the thyrse of an Ampelocissus-like ancestor and that the thyrse is a morphological synapomorphy of the Vitis-Ampelocissus clade.

1 - University Of Alaska Museum Of The North, Herbarium (ALA) And Dept. Of Biology And Wildlife, University Of Alaska Fairbanks, 907 Yukon Dr., Fairbanks, AK, 99775, USA
2 - 70 Dumbarton St., Guelph, ON, N1E 3T6, Canada
3 - University Of Guelph, Molecular And Cellular Biology, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
4 - Smithsonian Institution, Botany, MRC-166 National Museum Of Natural History, 10th St. & Constitution Ave., NW, MRC 166, Washington/DC, N/A, 20013-7012, USA

Keywords:
Ampelocissus
Vitis-Ampelocissus clade
Pterisanthes
Vitaceae
lamellate inflorescence
thyrse.

Presentation Type: Oral Paper:Papers for Sections
Session: 5
Location: Salon 9/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 8:30 AM
Number: 5003
Abstract ID:731
Candidate for Awards:None