Page 553 |
A
Review of Arisaema (Araceae) in North America: Nine species instead of
two?
Robert
Wyatt & Ann Stoneburner
ABSTRACT
The
most recent treatment of North American Arisaema recognizes only two species: A.
triphyllum and A. dracontium.
Much of the variation, especially in the triphyllum
complex is attributed to rampant hybridization, for
which there is little to no evidence. We provide arguments for recognizing at
least nine species, though some of these taxa need verification involving
additional fieldwork and DNA sequencing. We arrived at our conclusions based on
examination of herbarium specimens (including critical collections made during
two never-published doctoral studies), field observations of the species,
recent data reported by contributors to iNaturalist,
and critical examination of the literature. Within the triphyllum
complex, we recognize six species: A. triphyllum,
A. pusillum, A. stewardsonii,
A. quinatum, A. acuminatum, and A. sp. nov. A. Most authors have
treated these as subspecies, varieties, or forms, if they have been recognized
at all. All are diploid with n = 28 except for A. triphyllum,
which is a tetraploid with n = 56. Within the dracontium
complex, we recognize three species: A. dracontium,
A. macrospathum, and A. sp. nov. B. Again, there has been much confusion
surrounding these taxa, but only A. dracontium is
known to be tetraploid with n = 56.
KEYWORDS
Arisaema, distribution, ecology,
hybridization, North America, phylogeny, sex switching, systematics.