Survey of the vascular plants

Survey of the vascular plants

Why we put what where and to determine families

Why we put what where and to determine families

Outline

• How is relatedness among plant families determined?

• Different representative phylogenetic trees

• Using a synoptic key• Tips for learning plant families

How were plant families related?

• Relatedness among plant families was determined in the past primarily by floral traits

• Linnaeus used plant sexual organs as a primary basis in distinguishing families and genera.

Family Relatedness Now

• With the advent of molecular technology, there are many other ways to determine relatedness.

• Mostly, phylogenetic work is now done according actual differences in the DNA chloroplast genes

• The goal is to always create a monophyletic group

Monophyletic Groups

• A group containing only and all descendents of a common ancestor, and it is often characterizable by apomorphies, that is, shared, derived characters that appeared in the ancestral lineage or stem clade of that monophyletic group.

Cronquist classification system

http://www.mobot.org/MOBOT/research/APweb/welcome.html

From the Missouri Botanic Garden

Note that these are only to order, but we focus on the family

Mostly based on APG

Another example of a flowering plant phylogeny

Amborella

A.P.G.

• Angiosperm Phylogeny Group• Group of scientists that wanted to

standardize the previous groupings• Based on molecular data –

monophyletic groups• See chapter 6 for more info• Two seminal papers resulted• APG or APG I• APG II

APG II

• Published in 2003• Made clarifications from the 1998

paper• Basically just incorporated newer

molecular data• Always changing and being

revised, but with a good standard, that of the monophyletic group

An update of the Angiosperm Phylogeny Group classification for the orders and families of

flowering plants: APG IITHE ANGIOSPERM PHYLOGENY GROUP

A revised and updated classification for the families of the flowering plants is provided. Newly adopted orders include Austrobaileyales, Canellales, Gunnerales, Crossosomatales and Celastrales. Pertinent literature published since the first APG classification is included, such that many additional families are now placed in the phylogenetic scheme. Among these are Hydnoraceae (Piperales), Nartheciaceae (Dioscoreales), Corsiaceae (Liliales), Triuridaceae (Pandanales), Hanguanaceae (Commelinales), Bromeliacae, Mayacaceae and Rapateaceae (all Poales),

Why focus on the family?

• Over 400,000 plant species• Only about 400 plant families• Many families are already

monophyletic

Synoptic key

• These keys define major characteristics of a taxon

• Page 128-129 in your book• Useful to help in your discovery of

plant families• Let’s try it out!

Using a Synoptic Key

• Keys are great, but if you can recognize a family, you can go a lot quicker

• None of you need a key to recognize a conifer now (at least I hope not)

• We will focus on knowing families

Tips for learning families

• Practice keying plants to family• Practice keying plants to genus • Consult books and the internet• Prepare a set of

one-character/family tables• Make a family/character table• Flash cards• Study with friends

One Character Table

Superior Inferior Both

GrossulariaceaeOnagraceae

RosaceaeSaxifragaceae

CaprifoliaceaeApiaceae

EricaceaeLiliaceae

BetulaceaeFagaceae

Class / Trait Table

Character Magnoliopsida Liliopsida

Cotyledons Usually 2 Usually 1

Leaves Often reticulate veined Often parallel veined

Vascular Cambium Often present (ca. 50% woody) Absent

Primary Vascular Bundles Arranged in a ring Often scattered

Pollen Various types Monosulcate

Floral Parts Often in 4s or 5s Usually sets of 3

Root System Primary and adventitious Adventitious only