§ 45.21. Tentatively Undetermined.
Plant species classified as Tentatively Undetermined are as follows:
| Scientific Name | Common Name |
| Adiantum pedatum L. ssp. caulderi Cody | Northern Maidenhair Fern |
| Agalinis obtusifolia Raf. | False-Foxglove |
| Aletris farinosa L. | Colic-Root |
| Ambrosia psilostachya DC. | Naked-Spiked Ambrosia |
| Amelanchier humilis Wieg. | Low Serviceberry |
| Amelanchier obovalis (Michx.) Ashe | Coastal Juneberry |
| Amelanchier sanguinea (Pursh) DC. | Roundleaf Serviceberry |
| Andropogon glomeratus (Walt.) BSP. | Bushy Bluestem |
| Antennaria solitaria Rydb. | Single-Headed Pussy-Toes |
| Arabis hirsuta (L.) Scop. | Western Hairy Rock-Cress |
| Aristida curtissii (Gray) Nash | Poverty Grass |
| Aristida longespica Poir. var. geniculata (Raf.) Fern. | Long-Spike Three-Awned Grass |
| Aristolochia macrophylla Lam. | Pipevine |
| Asclepias variegata L. | White Milkweed |
| Aster dumosus L. | Bushy Aster |
| Aster ericoides L. | White Heath Aster |
| Aster firmus Nees | Firm Aster |
| Carex buxbaumii Wahlenb. | Brown Sedge |
| Carex crawfordii Fern. | Crawford’s Sedge |
| Carex haydenii Dewey | Cloud Sedge |
| Carex limosa L. | Mud Sedge |
| Carex longii Mackenzie | Long’s Sedge |
| Carex lupuliformis Sartwell ex Dewey | False Hop Sedge |
| Carex meadii Dewey | Mead’s Sedge |
| Carex mesochorea Mackenzie | Midland Sedge |
| Cassia marilandica L. | Wild Senna |
| Castilleja coccinea (L.) Spreng. | Scarlet Indian Paintbrush |
| Chasmanthium latifolium (Michx.) Yates | Wild Oat |
| Chenopodium capitatum (L.) Aschers. | Strawberry Goosefoot |
| Coeloglossum viride (L.) Hartman | Long-Bracted Green Orchid |
| Corallorrhiza wisteriana Conrad | Spring Coral-Root |
| Crataegus brainerdii Sarg. | Brainerd’s Hawthorne |
| Crataegus mollis (Torr. & Gray) Scheele | Downy Hawthorne |
| Cuscuta cephalanthi Engelm. | Button-Bush Dodder |
| Cuscuta corylii Engelm. | Hazel Dodder |
| Cuscuta polygonorum Engelm. | Smartweed Dodder |
| Cyperus odoratus L. | Rusty Flatsedge |
| Cyperus tenuifolius (Steud.) Dandy | Thin-Leaved Flatsedge |
| Cystopteris laurentiana (Weatherby) Blasdell | Laurentian Bladder-Fern |
| Desmodium glabellum (Michx.) DC. | Tall Tick-Trefoil |
| Desmodium nuttallii (Schindl.) Schub. | Nuttall’s Tick-Trefoil |
| Dracocephalum parviflorum Nutt. | American Dragonhead |
| Elatine minima (Nutt.) Fisch. & Mey | Small Water-Wort |
| Elodea canadensis L. C. Rich. | Broad Waterweed (Male Plants) |
| Elymus virginicus L. var. submuticus Hook. | Wild Rye |
| Epilobium palustre L. | Marsh Willow-Herb |
| Eupatorium rotundifolium L. | Round-Leaved Thoroughwort |
| Filipendula rubra (Hill) B. L. Robins. | Queen-of-the-Prairie |
| Gentiana alba Muhl. | Yellow Gentian |
| Gentiana saponaria L. | Soapwort Gentian |
| Gentiana villosa L. | Striped Gentian |
| Glyceria acutiflora Torr. | Sharp-Flowered Manna-Grass |
| Goodyera tesselata Lodd. | Checkered Rattlesnake-Plantain |
| Gratiola aurea Pursh | Golden Hedge-Hyssop |
| Gymnocarpium appalachianum Pryer & Windham (Morris Arboretum, 1992, Pennsylvania Flora Database) | Appalachian Oak Fern |
| Hedyotis purpurea (L.) Torr. & Gray | Purple Bluet |
| Hypericum drummondii (Grev. & Hook) Torr. & Gray | Nits-and-Lice |
| Juncus biflorus Elliott (Gleason, H. A. and A. Cronquist,, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Grass-Leaved Rush |
| Lathyrus palustris L. | Vetchling |
| Lemna turionifera Landolt (Morris Arboretum, 1992, Pennsylvania Flora Database) | Winter Duckweed |
| Leucothoe racemosa (L.) Gray | Swamp Dog-Hobble |
| Liatris scariosa (L.) Willd. var. novae-angliae Lunell | New England Gay-Feather |
| Liatris scariosa (L.) Willd. var. nieuwlandii Lunell | Nieuwland’s Gay-Feather |
| Lonicera hirsuta Eat. | Hairy Honeysuckle |
| Luzula bulbosa (Wood) Rybd. | Common Wood-Rush |
| Lysimachia quadriflora Sims. | Four-Flowered Loosestrife |
| Lythrum alatum Pursh | Winged Loosestrife |
| Malaxis brachypoda (Gray) Fern. | White Adder’s Mouth |
| Meehania cordata (Nutt.) Britt. | Heartleaf Meehania |
| Muhlenbergia cuspidata (Nutt.) Rydb. | Sharp-Pointed Muhly |
| Nuphar lutea (L.) Sibthorp & Sm. ssp. pumilum (Timm) E.O. Beal | Yellow Cowlily |
| Oenothera pilosella Raf. | Evening-Primrose |
| Oxydendrum arboreum (L.) DC. | Sourwood |
| Oxypolis rigidior (L.) Raf. | Stiff Cowbane |
| Panicum annulum Ashe (Morris Arboretum, 1992, Pennsylvania Flora Database) | Annulus Panic-Grass |
| Panicum bicknellii Nash (Fernald, M. L., Gray’s Manual of Botany, 1970, Eighth edition) | Bicknell’s Panic-Grass |
| Panicum boreale Nash (Gleason, H. A. and A. Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Northern Witchgrass |
| Panicum commonsianum Ashe var. commonsianum (Morris Arboretum, 1992, Pennsylvania Flora Database) | Commons’ Panic-Grass |
| Panicum flexile (Gattinger) Scribn. (Gleason, H. A. and A. Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Wiry Witchgrass |
| Panicum longifolium Torr. (Gleason, H. A. and A. Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Long-Leaf Panic-Grass |
| Panicum longiligulatum Nash (Morris Arboretum, 1992, Pennsylvania Flora Database) | Long-Ligule Panic-Grass |
| Panicum lucidum Ashe (Fernald, M. L., Gray’s Manual of Botany, 1970, Eighth edition) | Shining Panic-Grass |
| Panicum recognitum Fern. (Morris Arboretum, 1992. Pennsylvania Flora Database) | Fernald’s Panic-Grass |
| Panicum villosissimum Nash (Gleason, H. A. and A. Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Long-Haired Panic-Grass |
| Panicum yadkinense Ashe (Gleason, H. A. and A. Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Yadkin River Panic-Grass |
| Paronychia fastigiata (Raf.) Fern. var. nuttallii (Small) Fern. | Whitlow Wort |
| Paronychia fastigiata (Raf.) Fern. var. paleacea Fern. | Chaffy Whitlow Wort |
| Parthenium intergrifolium L. | American Fever-Few |
| Paspalum floridanum (Michx.) var. glabratum Engelm. ex Vasey | Florida Beadgrass |
| Paspalum laeve (Michx.) var. pilosum Scribn. | Field Beadgrass |
| Paspalum setaceum Michx. | Slender Beadgrass |
| Phlox pilosa L. | Downy Phlox |
| Phyla lanceolata (Michx.) Greene | Lance Fog-Fruit |
| Physalis virginiana P. Mill. | Virginia Ground-Cherry |
| Platanthera ciliaris (L.) Lindl. | Yellow Fringed Orchid |
| Platanthera hookeri (Torr. ex Gray) Lindl. | Hooker’s Orchid |
| Platanthera peramoena (Gray) Gray | Purple-Fringeless Orchid |
| Pluchea odorata (L.) Cass. | Shrubby Camphor-Weed |
| Poa languida A. S. Hitchc. | Drooping Bluegrass |
| Podostemum ceratophyllum Michx. | Riverweed |
| Polygala polygama Walt. | Racemed Milkwort |
| Polygonella articulata (L.) Meisn. | Eastern Jointweed |
| Polygonum amphibium L. var. stipulaceum (Coleman) Fern. | Stipuled Water-Smartweed |
| Polygonum ramosissimum Michx. | Bushy Knotweed |
| Potamogeton filiformis Pers. | Slender Pondweed |
| Potamogeton illinoensis Morong | Illinois Pondweed |
| Potamogeton oakesianus J. W. Robbins | Oakes’ Pondweed |
| Potamogeton perfoliatus L. | Clasping-Stemmed Pondweed |
| Pycnanthemum pilosum Nutt. | Hairy Mountain-Mint |
| Ranunculus flammula L. | Lesser Spearwort |
| Ranunculus trichophyllus Chaix (Gleason, H. A. and A. Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Northeastern White Water-Crowfoot |
| Ratibida pinnata (Vent.) Barnh. | Gray-Headed Prairie Coneflower |
| Rhamnus alnifolia L’Her | Alder-Leaved Buckthorn |
| Rhynchospora globularis (Chapman) Small | Small Globe Beak-Rush |
| Ribes lacustre (Pers.) Poir. | Swamp Currant |
| Rorippa palustris (L.) Besser var. palustris (Gleason, H. A. and A Cronquist, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 1991, Second Edition) | Yellow Cress |
| Rosa virginiana P. Mill. | Virginia Rose |
| Rubus cuneifolius Pursh | Sand Blackberry |
| Rubus setosus Bigelow | Small Bristleberry |
| Rumex hastatulus Baldw. ex Ell. | Heart-Winged Sorrell |
| Salix petiolaris Sm. | Meadow Willow |
| Salvia reflexa Hornem. | Lance-Leaved Sage |
| Samolus parviflorus Raf. (Fernald, M. L., Gray’s Manual of Botany, 1970, Eighth edition) | Pineland Pimpernel |
| Saxifraga micranthidifolia (Haw.) Steud. | Lettuce Saxifrage |
| Scleria triglomerata Michx. | Whip Nut-Rush |
| Scutellaria saxatilis Riddell | Rock Skullcap |
| Senecio plattensis Nutt. | Prairie Ragwort |
| Sisyrinchium albidum Raf. | Blue-Eyed Grass |
| Solidago purshii Porter | Pursh’s Goldenrod |
| Solidago rigida L. | Hard-Leaved Goldenrod |
| Spiranthes tuberosa Raf. | Little Ladies’-Tresses |
| Spirodela punctata (Mey.) C. H. Thompson | Eastern Water-Flaxseed |
| Stachys hyssopifolia Michx. | Hyssop Hedge-Nettle |
| Stylosanthes biflora (L.) BSP. | Pencil-Flower |
| Taxus canadensis Marsh. | American Yew |
| Tradescantia ohiensis Raf. | Ohio Spiderwort |
| Trillium flexipes Raf. | Declined Trillium |
| Triosteum angustifolium L. | Yellow-Leaved Tinker’s-Weed |
| Tripsacum dactyloides (L.) L. | Eastern Gamma-Grass |
| Uvularia puberula Michx. | Mountain Bellwort |
| Veronica catenata Pennell | Pennell’s Speedwell |
| Viburnum trilobum Marsh. | Highbush Cranberry |
| Viola nephrophylla Greene | Northern Bog Violet |
| Viola renifolia Gray | Kidney-Leaved White Violet |
| Viola tripartita Ell. | Three-parted Violet |
| Vitis cinerea var. baileyana Munson | Possum-Grape |
| Wolffia borealis (Engelm.) Landolt (Morris Arboretum, 1992, Atlas of the Flora of Pennsylvania) | Dotted Water-Meal |
| Zanichellia palustris L. | Horned Pondweed |
The provisions of this § 45.21 adopted December 4, 1987, effective January 1, 1988, 17 Pa.B. 5027; amended June 18, 1993, effective June 19, 1993, 23 Pa.B. 2816. Immediately preceding text appears at serial pages (123456) to (123460).
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