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The Genus Isoetes (Lycophyta) in the Southeastern United States

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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The Genus Isoetes (Lycophyta) in the Southeastern United States

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  1. The Genus Isoetes (Lycophyta) in the Southeastern United States Lytton John Musselman, Rebecca D Bray W Carl Taylor 10 April 2007

  2. The Genus Isoetes (Lycophyta) in the Southeastern United States A quarter century review for field botanists

  3. What is a quillwort? Field characters

  4. 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

  5. Obligate hydrophyte with spirally arranged leaves

  6. groove on adaxial surface, four air chambers

  7. groove on adaxial surface, four air chambers

  8. diaphragm groove on adaxial surface, four air chambers

  9. arising from a “corm-like” structure bearing forked root tips

  10. All quillworts look similar! Size can range from 0.01 to 2.0 m Isoetes butleri Isoetes melanopoda Isoetes mattaponica

  11. All quillworts look similar! Isoetes butleri Kentucky Isoetes stellebossiensis South Africa Isoetes olympica Syria

  12. All quillworts look similar! Lots of variability in size in most species Isoetes hyemalis Submersed Terrestrial

  13. The exception to the spiraled leaves, corm structure, and forked roots is Isoetes tegetiformans

  14. Then and Now 1985--Three species of quillworts in Flora of the Carolinas 2007--Six in Weakley

  15. Then and Now 1985--No hybrids 2007--Isoetes are

  16. Then and Now 1985--No hybrids 2007--Isoetes are Promiscuous allcan be expected to hybridize

  17. Then and Now 1985--few species with scales 2007-- all Isoetes have scales

  18. Then and Now 1985--few species with scales 2007-- all Isoetes have scales

  19. Scales and Phyllopodia are Different Scales are modified leaves, phyllopodia are indurated leaf bases

  20. Then and Now 1985--considered infrequent or rare 2007-- most counties in the Southeast probably have/had Isoetes

  21. Then and Now 1985--little vegetative reproduction 2007-- probably widespread

  22. 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

  23. Then and Now 1985--Megaspores essential for determination 2007-- Megaspores still necessary for diploid species

  24. Megaspores confusing for most tetraploids because of similar ornamentation Isoetes hyemalis Isoetes georgiana

  25. 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

  26. The Genus as Currently Understood • I. Basic Diploids (2n=22) • Conservation concern • I. mattaponica • melanospora • I. tegetiformans

  27. 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

  28. 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

  29. The Genus as Currently Understood III. Three Described Allohexaploids (2n=66) Isoetes georgiana (includes I. boomii) I. junciformis I. microvela

  30. 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

  31. The Genus as Currently Understood IV. One Allooctoploid (2n=88) Isoetes tennesseensis of conservation concern

  32. The Genus as Currently Understood V. One Allodecaploid (2n=110) Isoetes lacustris Of conservation concern in the South, abundant across Canada

  33. 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)

  34. Hybrids spores are misshapen and of varying sizes

  35. Hybrids exhibit heterosis Isoetes × altonharvillii Isoetes valida Isoetes engelmannii

  36. 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.

  37. How are Isoetes species identified?

  38. Answer: With difficulty!

  39. Megaspores have traditionally been the most reliable way to identify quillworts

  40. Until the advent of molecular techniques, megaspores were used to suggest patterns of phylogeny

  41. How many species have been extirpated in the past twenty five years? Isoetes “riparia”, Alligator River, North Carolina

  42. 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

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