PRELIMINARY INDEX OF NATURAL VEGETATION ALLIANCES FOR IOWA (Version 4.1,
5/98)^1^

John Pearson, Iowa Natural Heritage Inventory

Tom Rosburg, Plant Ecologist, Iowa Gap Project

Erwin E. Klaas, Principal Investigator, Iowa Gap Project

This index of natural vegetation alliances for Iowa closely follows
Drake and Faber-Langedoen\'s *An Alliance Level Classification of the
Vegetation of the Midwestern United States* (DFL) (May 1997). Species
enclosed in parentheses may occur in place of or as co-dominants. Page
numbers refer to alliance descriptions in DFL. We include 20 alliances
(\*\*\*) that were described in DFL but Iowa was omitted from the
geographic range. We also include 8 alliances (###) that were not
described in DFL. An early draft of this index was reviewed by a panel
of botanists (John Pearson, Tom Rosburg, Susan Galatowitsch, Donald
Farrar, and William Norris). Pearson, Rosburg and Klaas then reviewed
all comments and prepared version 4.0. Shading indicates names of
species added by the authors to DFL\'s nomenclature; deletions are
indicated by strike outs.

**CLASS CLASS**

**CODE**

Formation Formation

code

**I FOREST** (Generally, \>60% canopy of tree species with crowns
interlocking.) PAGE

I.A.8.N.b. Rounded-crowned temperate or subpolar needle-leaved evergreen
forest

1\. *Pinus strobus* Forest Alliance 41

I.A.8.N.c. Conical-crowned temperate or subpolar needle-leaved evergreen
forest

2\. **\###** *Juniperus virginiana* Forest Alliance (Not listed as a
forest alliance in DFL but see comments under Woodland p. 177)

I.B.2.N.a. Lowland or submontane cold-deciduous forest (Note:
\"lowland\" here does not mean bottomland)

3\. *Acer saccharum (A. nigrum)* - *Tilia americana* - (*Quercus rubra*)
Forest Alliance (*A. nigrum* may occur in central Iowa) 65

4\. **\*\*\*** *Fraxinus pennsylvanica* - (*Ulmus americana - Julgans
nigra - Celtis occidentalis - Robinia pseudoacacia - Acer negundo -
Populus* spp. )^2^ Forest Alliance (Usually occurs on distrubed sites)
73

5\. *Quercus alba* - *(Quercus rubra*, *Carya* spp.) Forest Alliance 77

6\. *Quercus macrocarpa* Forest Alliance 81

7\. **\*\*\*** *Quercus muehlenbergii* Forest Alliance 83

8\. **\*\*\*** *Quercus rubra - Acer saccharum - (Quercus ~~alba~~
spp.)* Forest Alliance 86

> *Quercus velutina* - *Quercus ellipsoidalis* Forest Alliance (In Iowa
> these species seldom occur together as co-dominants) 93

9\. **\###** *Quercus imbricaria* Forest Alliance (Occurs along edges of
limestone bluffs in eastern Iowa)

I.B.2.N.b. Montane or boreal cold-deciduous forest

10\. *Populus tremuloides (Populus grandidentata)* Forest Alliance 99

I.B.2.N.d. Temporarily flooded cold-deciduous forest (This formation is
usually bottomland/floodplain forest)

11\. **\*\*\*** *Acer negundo - (Gleditsia triacanthos - Crataegus*
spp.) Forest Alliance (Usually occurs on disturbed sites) 10112. *Acer
saccharinum* Temporarily Flooded Forest Alliance 103

13\. *Betula nigra* - (*Platanus occidentalis*) Temporarily Flooded
Forest Alliance 107

14\. *Fraxinus pennsylvanica* - *Ulmus americana* - (*Celtis*
*occidentalis, ~~laevigata~~* - *Juglans nigra*)^2^ Temporarily Flooded
Forest Alliance 113

15\. *Populus deltoides* Temporarily Flooded Forest Alliance 115

16\. **\*\*\*** *Quercus macrocarpa* - *Quercus bicolor* - (*Carya
laciniosa*) Temporarily Flooded Forest Alliance 120

17\. **\*\*\*** *Salix nigra (S. amygdaloides)* Temporarily Flooded
Forest Alliance 121

I.B.2.N.e. Seasonally flooded cold-deciduous forest

18\. **\*\*\*** *Quercus palustris* - (*Quercus bicolor*) Seasonally
Flooded Forest Alliance 127

I.C.3.N.a. Mixed needle-leaved evergreen - cold-deciduous forest

19\. **\###** *Juniperus virginiana - Quercus macrocarpa* Forest
Alliance (Occurs on distrubed prairie sites lacking periodic fire)

**II WOODLAND** (Open stands of tree species with 25-60% canopy cover.)

II.A.4.N.b. Conical-crowned temperate or subpolar needle-leaved
evergreen woodland

20\. **\*\*\*** *Juniperus virginiana* Woodland Alliance (see comments
in DFL, p. 177, common in Iowa on disturbed prairies and pastures) 177

II.B.2.N.a. Cold-deciduous woodland

21\. *Quercus macrocarpa* - *Quercus* (*alba*, *velutina*) Woodland
Alliance 191

22\. *Quercus macrocarpa* Woodland Alliance 193

23\. *Quercus muehlenbergii* Woodland Alliance 195

II.B.2.N.b. Temporarily flooded cold-deciduous woodland

24\. **\*\*\*** *Populus deltoides* Temporarily Flooded Woodland
Alliance 199

II.C.3.N.a. Mixed needle-leaved evergreen - cold-deciduous woodland

25\. **\###** *Juniperus virginiana - (Quercus macrocarpa)* Woodland
Alliance (Occurs on prairies in the absence of periodic fire)

**III SHRUBLAND** (Generally shrubs \>0.5 m tall forming \>25% cover
with \<25% tree cover.)

III.B.2.N.a. Temperate cold-deciduous shrubland

26\. **\###** *Cornus* spp. - *Rhus* spp. - (*Symphoricarpus* spp.)
Shrubland Alliance

III.B.2.N.d. Temporarily Flooded Shrubland Alliance

27\. *Salix exigua (=S. interior)* Temporarily Flooded Shrubland
Alliance 232

III.B.2.N.e. Seasonally flooded cold-deciduous shrubland

28\. *Alnus incana* Seasonally Flooded Shrubland Alliance 238

29\. *Cornus ~~sericea~~* spp. - *Salix* spp. Seasonally Flooded
Shrubland Alliance 241

III.B.2.N.f. Semipermanently flooded cold-deciduous shrubland

30\. *Cephalanthus occidentalis* Semipermanently Flooded Shrubland
Alliance 243

III.B.2.N.g. Saturated cold-deciduous shrubland

31\. *Betula pumila* - (*Salix* spp.) Saturated Shrubland Alliance 245

**IV DWARF-SHRUBLAND**

> None in Iowa

**V HERBACEOUS VEGETATION** (\<25% canopy cover made up of trees or
shrub species. Herbs form at least 25% of canopy cover.)

V.A.5.N.a. Tall sod temperate grassland

32\. *Andropogon gerardii* - (*~~Calamagrostis canadensis~~*, *Panicum
virgatum*) Herbaceous Alliance 258

33\. *Andropogon gerardii* - (*Sorghastrum nutans*) Herbaceous Alliance
260

34\. *Andropogon gerardii - Schizachyrium scoparium* - *Sorghastrum
nutans* Herbaceous Alliance 266

V.A.5.N.c. Medium-tall sod temperate or subpolar grassland

35\. *Schizachyrium scoparium (~~Sporobolus cryptandrus~~, Lithospermum
carolinense, Cyperus schweinitzii)* Herbaceous Alliance (Sand Prairies)
277

36\. *Schizachyrium* *scoparium* - *Bouteloua curtipendula* Herbaceous
Alliance 279

V.A.5.N.j. Temporarily flooded temperate or subpolar grassland

37\. **\*\*\*** *Andropogon gerardii - (Calamagrostis canadensis,
Sorghastrum nutans*) Temp. Flooded Herbaceous Alliance 291

38\. *Carex* *lanuginosa* Temporarily Flooded Herbaceous Alliance 292

39\. *Spartina pectinata* Temporarily Flooded Herbaceous Alliance 302

V.A.5.N.k. Seasonally flooded temperate or subpolar grassland

40\. **\*\*\*** *Calamagrostis canadensis* Seasonally Flooded Herbaceous
Alliance 304

41\. *Carex atherodes (Carex vesicaria)* Seasonally Flooded Herbaceous
Alliance 310

42\. *Carex lacustris* Seasonally Flooded Herbaceous Alliance 312

43\. **\*\*\*** *Carex (rostrata, utriculata*) Seasonally Flooded
Herbaceous Alliance 306

44\. *Carex stricta (Carex haydenii)* Seasonally Flooded Herbaceous
Alliance 313

45\. ~~*Cladium mariscoides* Seasonally Flooded Herbaceous Alliance~~
(*C. mariscoides* does not occur in Iowa) 315

46\. **\*\*\*** *Phalaris arundinacea* Seasonally Flooded Herbaceous
Alliance 317

47\. **\*\*\*** *Scirpus fluviatilis* Seasonally Flooded Herbaceous
Alliance 320

48\. **\*\*\*** *Typha* spp. - (*Scirpus* spp. - *Juncus* spp.)
Seasonally Flooded Herbaceous Alliance 324

V.A.5.N.l. Semipermanently flooded temperate or subpolar grassland

49\. **\*\*\*** *Phragmites australis* Semipermanently Flooded
Herbaceous Alliance 326

50\. **\###** *Sagittaria latifolia (S. rigida)* Semipermanently Flooded
Herbaceous Alliance (Common in Mississippi River backwaters)

51\. *Scirpus acutus (S. fluviatilis, tabernaemontani)*^2^ 328

52\. *Typha* (*angustifolia*, *latifolia*) - (*Scirpus* spp.)
Semipermanently Flooded Herbaceous Alliance 334

53\. *Zizania* (*aquatica*, *palustris*) Semipermanently Flooded
Herbaceous Alliance 336

V.A.5.N.m. Saturated temperate or subpolar grassland

54\. *Carex lanuginosa - (~~C. nebrascensis~~)* - *Scirpus* spp.
Saturated Herbaceous Alliance 340

55\. **\###** *Carex stricta* Saturated Herbaceous Alliance (Rich Fen)

56\. *~~Carex oligosperma~~ - Carex lasiocarpa* (*Spagnum* spp.)
Saturated Herbaceous Alliance (Poor Fen) 343

57\. **\*\*\*** *Carex* spp. - *Typha* spp. Saturated Herbaceous
Alliance 344

58\. *Carex* spp. - *Rhynchospora capillacea - Lobelia kalmii*^2^
Saturated Herbaceous Alliance (Calcareous Fen) 345

V.A.6.N.c. Tall temperate grassland with a sparse cold-deciduous tree
layer (\"Savanna\")

59\. **\*\*\*** *Populus deltoides* Wooded Herbaceous Alliance (*P.
deltoides* occasionally invades moist prairie sites) 346

60\. *Quercus macrocarpa* - (*Quercus alba*) Wooded Herbaceous Alliance
347

61\. *Quercus velutina* - (*Quercus ellipsoidalis*) Wooded Herbaceous
Alliance 349

V.A.6.N.f. Medium-tall temperate or subpolar grassland with a sparse
needle-leaved evergreen or mixed tree layer (\"Savanna\")

62\. *Schizachyrium scoparium* - *Bouteloua curtipendula (Juniperus
virginiana - Quercus* spp.) Evergreen or Mixed Wooded Herbaceous 355

V.A.7.N.p. Saturated temperate or subpolar grassland with a sparse
cold-deciduous shrub layer

63\. ~~*Pentaphylloides* *floribunda* / *Carex* (*flava*, *interior*,
*lasiocarpa*, *sterilis*) Saturated Shrub Herbaceous Alliance~~ (Not
known to occur in Iowa) 373

V.B.2.N.a. Tall temperate or subpolar perennial forb vegetation

64\. *Impatiens pallida - Cystopteris bulbifera - Adoxa moschatellina*
Herbaceous Alliance 376

V.B.2.N.d. Temporarily flooded temperate or subpolar perennial forb
vegetation

65\. **\*\*\*** *Polygonum* spp. - Mixed Forb Temporarily Flooded
Herbaceous Alliance 380

V.B.2.N.e. Semipermanently flooded temperate perennial forb vegetation

66\. **\*\*\*** *Nelumbo lutea* Semipermanently Flooded Herbaceous
Alliance 382

67\. *Symplocarpus foetidus - Caltha palustris* Saturated Herbaceous
Alliance 383

V.C.2.N.a. Permanently flooded temperate or subpolar hydromorphic rooted
vegetation

68\. *Nuphar* *lutea* - *Nymphaea* *odorata* Permanently Flooded
Herbaceous Alliance 385

69\. *Potamogeton* spp. - *Ceratophyllum* spp. - (*Myriophyllum* spp. -
*Elodea* spp.)^2^ Permanently Flooded Herbaceous Alliance 388

70\. *Ruppia maritima* Permanently Flooded Herbaceous Alliance (Rare or
non-existent) 390

71\. *Vallisneria americana* Permanently Flooded Herbaceous Alliance
(Restricted to Mississippi River) 391

**VI NONVASCULAR VEGETATION**

> None in Iowa

^1^This is a working draft of the Natural Vegetation Alliances for Iowa.
Occurrence and distribution of many of the alliances listed have not
been verified. This document should not be cited without first
contacting the authors.

^2^Species presence and order of dominance variable; often occurring on
disturbed sites.

**Literature Cited:**

Drake, Jim and Don Faber-Langendoen. 1997. *An Allicance Level
Classification of the Vegetation of the Midwestern United States*. A
Report to the University of Idaho, Cooperative Fish and Wildlife
Research Unit and National Gap Analysis Program. The Nature Conservancy,
Midwest Conservation Science Department, Minneapolis, MN. 396 pp.