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The Genus Isoetes (Lycophyta) in the Southeastern United States. Lytton John Musselman, Rebecca D Bray W Carl Taylor. 10 April 2007. The Genus Isoetes (Lycophyta) in the Southeastern United States. A quarter century review for field botanists. What is a quillwort? Field characters.

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slide1

The Genus Isoetes (Lycophyta) in the

Southeastern United States

Lytton John Musselman, Rebecca D Bray

W Carl Taylor

10 April 2007

slide2

The Genus Isoetes (Lycophyta) in the

Southeastern United States

A quarter century review for field botanists

slide3

What is a quillwort?

Field characters

slide4

Obligate hydrophyte with spirally arranged leaves with a groove on the adaxial surface, four air chambers; arising from a “corm-like” structure bearing forked root tips

slide6

groove on adaxial

surface, four air chambers

slide7

groove on adaxial

surface, four air chambers

slide8

diaphragm

groove on adaxial

surface, four air chambers

slide9

arising from

a “corm-like” structure bearing forked

root tips

slide10

All quillworts look similar!

Size can range from 0.01 to 2.0 m

Isoetes butleri

Isoetes melanopoda

Isoetes mattaponica

slide11

All quillworts look similar!

Isoetes butleri

Kentucky

Isoetes stellebossiensis

South Africa

Isoetes olympica

Syria

slide12

All quillworts look similar!

Lots of variability in size in most species

Isoetes

hyemalis

Submersed

Terrestrial

slide13

The exception to the spiraled leaves,

corm structure, and forked roots is

Isoetes tegetiformans

slide14

Then and Now

1985--Three species of quillworts in

Flora of the Carolinas

2007--Six in Weakley

slide15

Then and Now

1985--No hybrids

2007--Isoetes are

slide16

Then and Now

1985--No hybrids

2007--Isoetes are Promiscuous

allcan be expected to hybridize

slide17

Then and Now

1985--few species with scales

2007-- all Isoetes have scales

slide18

Then and Now

1985--few species with scales

2007-- all Isoetes have scales

slide19

Scales and Phyllopodia are Different

Scales are modified leaves, phyllopodia

are indurated leaf bases

slide20

Then and Now

1985--considered infrequent or rare

2007-- most counties in the Southeast

probably have/had Isoetes

slide21

Then and Now

1985--little vegetative reproduction

2007-- probably widespread

slide22

Then and Now

1985--little vegetative reproduction

2007-- probably widespread through

branching of the root stock

Isoetes flaccida, Putnam Co, FL

Unnamed tetraploid, Chesterfield Co, VA

slide23

Then and Now

1985--Megaspores essential for

determination

2007-- Megaspores still necessary for

diploid species

slide24

Megaspores confusing for most

tetraploids because of similar

ornamentation

Isoetes hyemalis

Isoetes georgiana

slide25

The Genus as Currently Understood

Taxonomically in the Southeast

I. Nine Basic Diploids (2n=22)

Isoetes butleri

I. engelmannii

I. flaccida

I. mattaponica

I. melanopoda

I. melanospora

I. “piedmontana’

I. tegetiformans

I. valida

slide26

The Genus as Currently Understood

  • I. Basic Diploids (2n=22)
  • Conservation concern
  • I. mattaponica
  • melanospora
  • I. tegetiformans
slide27

The Genus as Currently Understood

II. Seven Described Allotetraploids (2n=44)

Isoetes acadiensis

I. appalachiana

I. hyemalis

I. louisianensis

I. piedmontana

I. riparia

I. virginica

slide28

The Genus as Currently Understood

II. Allotetraploids (2n=44)

Conservation concerns

Cannot be accurately addressed

until we know more about the

phylogeny of these polyploids,

at least some of which are

polyphyletic

slide29

The Genus as Currently Understood

III. Three Described Allohexaploids (2n=66)

Isoetes georgiana (includes I. boomii)

I. junciformis

I. microvela

slide30

The Genus as Currently Understood

IV. Allohexaploids (2n=66)

Conservation concerns

Cannot be accurately addressed

until we know more about the

phylogeny of these polyploids,

at least some of which might be

polyphyletic

slide31

The Genus as Currently Understood

IV. One Allooctoploid (2n=88)

Isoetes tennesseensis

of conservation concern

slide32

The Genus as Currently Understood

V. One Allodecaploid (2n=110)

Isoetes lacustris

Of conservation concern in the South,

abundant across Canada

slide33

The Genus as Currently Understood

  • VI. Four named primary hybrids
  • Isoetes × altonharvillii (I. valida x I.
  • engelmannii, 2n=22)
  • I. × brittonii (I. engelmannii x I. riparia,
  • 2n=33)
  • I. × bruntonii (I. engelmannii x I. hyemalis,
  • 2n=33)
  • I. × carltaylorii (I. engelmannii x I. acadiensis,
  • 2n=33)
slide35

Hybrids exhibit heterosis

Isoetes × altonharvillii

Isoetes valida

Isoetes engelmannii

slide36

The Genus as Currently Understood

VI. New Taxa

There are several diploid populations that

deserve further study, these could be new

species.

We have several distinct tetraploid populations

but cannot formally name them until we

understand their phylogeny.

slide39

Megaspores have traditionally been the

most reliable way to identify quillworts

slide40

Until the advent of molecular techniques,

megaspores were used to suggest

patterns of phylogeny

slide41

How many species have been extirpated in the past twenty five years?

Isoetes “riparia”,

Alligator River,

North Carolina

slide42

Acknowledgements

Khalid Al Arid

Mohammad Al Zein

Jim Allison

Jay Bolin

Daniel Brunton

Cindy Caplen

Kerry Heafner

Jim Hickey

David Knepper

ODU Plant Research Group

Charlie Werth

Joe Winstead