Ulmus (Ulmaceae)
Ulmus americana
U Conn Plant Database
Ulmus americana
USDA APMRU
Ulmus americana
USDA APMRU
Plant:
Deciduous tree, to over 75 ft (23 m), arching, or spreading branches.
Alternate, simple leaves, 7.5-15 cm, ovate-oblong, unequal at base,
doubly serrate. American Elm has been decimated by the usually
fatal Dutch Elm Disease. Ulmus contains about 45 species native
to Asia [11], Europe and the Mediterranean [6], South and Central
America [7] and North America [7].
Pollen light micrograph:
Oblate, 35-40 µm., stephanoporate with 5 (4) oval pores, rugulate.
Easily recognized by its unique "brain-like" sculpture pattern
and pentagonal shape.
Pollen scanning electron micrograph (SEM)
Sculpture pattern complex.
Production and Dispersal:
Typically present in small percentages, but abundant production.
Characteristic of the Eastern Deciduous forest of North America.
Preservation:
Moderately well preserved.
Fossil Occurrence:
A characteristic species of the New World and Old World Tertiary, possibly
present in the the Maastrichtian
Hell Creek Flora.
The pollen of Cretaceous
Ulmoideipites krempii
is similar, but typically with 3 (4) pores and arci.
Ulmus pollen is difficult (impossible) to distinguish from that of
Zelkova. Pollen and macrofossils of both genera are present from
at least the Eocene of North America.
Elm is the key species
of the Atlantic period (Mid Holocene 8000 - 5000 yr B.P.) of the
European "Blytt Syrnander" sequence.
-
Plant
Sticklen, M.B., M.G. Bolyard, R.K. Hajela and L.C. Duchesne. 1991.
Molecular and cellular aspects of Dutch elm disease. Phytoprotection 72(1):1-13
Gil, L. and M.E. Garcia-Nieto Rivero. 1990.
[Paleobotanic and history of elms in the Iberian peninsula] Paleobotanica e historia de los olmos de la peninsula iberica. Chap. 2, pp. 29-65 in Los Olmos y la Graphiosis en Espana (L. Gil, ed.). ICONA
Pollen
Lappalainen, V. 1965
The Ulmus decline in postglacial pollen diagrams from southeastern Finland. The Geological Society Of America Special Paper 84
- The end-Atlantic Elm Decline
Pollen
- Ulmus Ulmaceae LM Uppsala
- Ulmus alata Ulmaceae SEM APMRU
- Ulmus americana Ulmaceae LM APMRU
- Ulmus americana Ulmaceae SEM APMRU
- Ulmus crassifolia Ulmaceae SEM APMRU
Owen K. Davis 06/00