Plant Watch List

The Plant Watch List (WL) is an unofficial, non-regulatory list of plants of known or suspected conservation concern that NHESP is interested in tracking.

Species are included on the list for a number of reasons:

1. The species is thought to be rare, declining, or vulnerable, but there is insufficient information on the condition, number and size of populations to make a determination (termed "Uncommon" in the "Reasons" for listing field)
2. The species was removed from the official regulatory list, but the Program believes it still is in need of some conservation attention (termed "MESA-Delisted" in the "Reasons" for listing field)  
3. The species is uncommon and there are uncertainties about the taxonomic status (termed "Taxonomic Issues" in the "Reasons" for listing field)
4. the species is uncommon and its status as a native or an introduced species is undecided (termed "Introduced?" in the "Reasons" for listing field)
5. The species is recently discovered or rediscovered in the Commonwealth and is placed on the Watch List to ensure it is tracked while botanists determine whether it is appropriate for proposal to the MESA List.

Plant Watch List

Scientific Name	Common Name	S Rank	New England Rank	G Rank	Reason	Synonym
Acalypha virginica	Three-seeded Mercury	S1S2		G5	Uncommon	Acalypha virginica var. virginica
Acer nigrum	Black Maple	S3		G5	MESA-Delisted	Acer saccharum ssp. nigrum; Acer saccharum var. nigrum
Achillea millefolium var. lanulosa	Seaside Yarrow	S3S4		G5T5	MESA-Delisted	Achillea lanulosa; Achillea millefolium var. lanulosa
Aletris farinosa	Colic-root	S4		G5	Decreasing
Amelanchier intermedia	Intermediate Shadbush, Intermediate Serviceberry	SNA		GNR	Taxonomic Issue	Amelanchier x intermedia
Amelanchier nantucketensis	Nantucket Shadbush	S3	1	G3Q	MESA-Delisted	Amelanchier x nantucketensis
Angelica lucida	Seaside-angelica	S2?	IND.	G5	Uncommon	Coelopleurum lucidum
Asclepias amplexicaulis	Clasping Milkweed	SNR		G5	Uncommon
Asclepias tuberosa	Orange Milk-weed	S4	3	G5	MESA-Delisted
Athyrium asplenioides	Southern Lady-fern	S2?		G5T5	Uncommon	Athyrium filix-femina var. asplenioides; Athyrium asplenioides
Atriplex glabriuscula	Prostrate Orache	S1S2		G5	Uncommon	Atriplex glabriuscula var. glabriuscula
Bartonia paniculata ssp. paniculata	Twining Screwstem	SNR	IND.	G5T5	Uncommon	Bartonia paniculata var. paniculata; Bartonia paniculata
Betula cordifolia	Heart-leaf Paper-birch	SNR		G5	Uncommon	Betula papyrifera var. cordifolia
Betula nigra	River Birch	S3	2	G5	Uncommon
Bidens beckii	Water Marigold	S2		G5	Uncommon	Megalodonta beckii
Boechera stricta	Drummond's Rockcress	S2S3		G5	Uncommon	Boechera angustifolia
Bolboschoenus fluviatilis	River Bulrush	S2		G5	MESA-Delisted	Scirpus fluviatilis; Schoenoplectus fluviatilis
Bolboschoenus novae-angliae	New England Bulrush	S1S2	2	G3	Uncommon	Scirpus subterminalis var. cylindricus; Scirpus cylindricus; Bolboschoenus x novae-angliae; Scirpus novae-angliae; Schoenoplectus novae-angliae
Botrychium angustisegmentum	Narrow Triangle Grape-fern	S2S3		G5T4T5	Uncommon	Botrychium lanceolatum ssp. angustisegmentum; Botrychium angustisegmentum
Botrychium matricariifolium	Daisy-leaf Moonwort	S2?		G5	Uncommon	Botrychium matricariaefolium
Botrychium oneidense	Blunt-lobed Grape-fern	S1S2	IND.	G4	Uncommon	Sceptridium oneidense
Botrychium simplex	Least Moonwort	S1S2		G5	Uncommon
Botrychium tenebrosum	Swamp Moonwort	S1S2		G5T4?	Uncommon	Botrychium tenebrosum
Bouteloua curtipendula	Side-oats Gamma grass	SNA	2	G5	Introduced?
Calamagrostis canadensis var. macouniana	Macoun's Reedgrass	SNR		G5T4T5	Uncommon
Calopogon tuberosus	Grass-pink	SNR		G5	Uncommon	Calopogon pulchellus
Calystegia silvatica ssp. fraterniflora	Short-stalked False Bindweed	S2	2	G5T5	Historic Rediscovered	Calystegia silvatica ssp. fraterniflorus; Convolvulus fraterniflorus; Calystegia sepium var. fraterniflora
Cardamine bulbosa	Spring-Cress	S2S3		G5	Uncommon	Cardamine rhomboidea
Cardamine maxima	Three-leaved Toothwort	S2?	IND.	G5	Uncommon	Dentaria maxima
Carex abscondita	Concealed Sedge	S2?		G5	Uncommon
Carex aestivalis	Summer-sedge	S2S3		G4	Uncommon
Carex aquatilis var. substricta	Water-sedge	SNR		G5T5	Uncommon	Carex substricta
Carex atherodes	Wheat Sedge	S1		G5
Carex bicknellii	Bicknell's Sedge	S1S2	IND.	G5	Uncommon
Carex buxbaumii	Buxbaum's Sedge	S2S3		G5	Uncommon
Carex cristatella	Crested Sedge	S2?		G5	Uncommon
Carex debilis var. debilis	Southern Stalked Sedge	SNR		G5T5	Uncommon	Carex debilis
Carex deflexa	Mountain Sedge	S1		G5	Historic Rediscovered
Carex diandra	Panicled Sedge	S1S2		G5	Uncommon
Carex emoryi	Emory's Sedge	S1		G5	Uncommon
Carex garberi	Elk Sedge	S1	2(a)	G5	Uncommon
Carex haydenii	Hayden's Sedge	S1S2		G5	Uncommon
Carex limosa	Mud Sedge	S2?		G5	Uncommon
Carex molesta	Troublesome Sedge	S1?		G5	Uncommon
Carex prairea	Praire-sedge	S1?		G5	Uncommon
Carex retrorsa	Hooked Sedge	S2S3		G5	Uncommon
Carex sparganioides	Bur-sedge	S4		G5	Uncommon?
Carex viridula ssp. viridula	Little Green Sedge	S1S2		G5T5	Uncommon	Carex viridula var. viridula
Caulophyllum giganteum	Early Blue Cohosh	S2S3		G4G5	Uncommon	Caulophyllum thalictroides var. giganteum
Chenopodium simplex	Maple-leaf Goosefoot	S3?		G5	Uncommon	Chenopodium hybridum; Chenopodiastrum simplex
Chenopodium standleyanum	Woodland-goosefoot	SNR	IND.	G5	Introduced?
Cirsium horridulum var. horridulum	Yellow Thistle	S2S3		G5T5	Uncommon
Corema conradii	Broom Crowberry	S3		G4	MESA-Delisted
Coreopsis rosea	Pink Tickseed	S3	1	G3	Uncommon
Crataegus biltmoreana	Biltmore Hawthorn	SNR		G5	Uncommon	Crataegus intricata var. biltmoreana
Crataegus keepii	Keep's Hawthorn	SNR		GNR	Uncommon?
Crataegus stonei	Stone's Hawthorn	S1	4	GNR	Uncommon
Crocanthemum dumosum	Bushy Rockrose	S3	1	G3	MESA-Delisted	Helianthemum dumosum
Cuscuta coryli	Pondshore-dodder	S1?	2	G4	Uncommon
Cuscuta polygonorum	Smartweed-dodder	S3S4		G4G5	Introduced?
Cyperus odoratus	Saltmarsh Flatsedge	S1S2	IND.	GNR	MESA-Delisted	Cyperus odoratus var. odoratus
Cyperus polystachyos	Texas Flatsedge	S2S3		G5	Uncommon	Pycreus polystachyos
Cystopteris laurentiana	Laurentian Bladder Fern	S2S3		G3	Uncommon	Cystopteris fragilis var. laurentiana; Cystopteris x laurentiana
Desmodium canescens	Hoary Tick-trefoil	S3	2	G5	Uncommon
Dichanthelium acuminatum ssp. acuminatum	Auburn Panic-grass	S1?		G5T5	Uncommon
Dioscorea villosa	Wild Yam	SNR		G5	Introduced?
Dryopteris campyloptera	Mountain Wood-fern	S3?		G5	Uncommon	Dryopteris austriaca
Dryopteris goldieana	Goldie's Fern	S3		G5	MESA-Delisted	Dryopteris goldiana
Elatine triandra	European Waterwort	SNR		G5	Introduced?	Elatine triandra var. triandra
Eleocharis engelmannii var. detonsa	Englemann's Spike-rush	S1S2		G5T3?	Uncommon
Eleocharis engelmannii var. engelmannii	Englemann's Spike-rush	S1S2		G5TNR	Uncommon
Eleocharis erythropoda	Redfoot Spike-rush	S3		G5	MESA-Delisted
Eleocharis melanocarpa	Black-fruited Spike-rush	S3		G4	MESA-Delisted
Eleocharis rostellata	Beaked or Saltmarsh Sedge	S2?	IND.	G5	Uncommon	Scirpus rostellatus
Elymus macgregorii	Early Wild Rye	S2?		G5	Uncommon
Elymus trachycaulus ssp. trachycaulus	Slender Wild Rye	SNR		G5T5	Uncommon	Elymus trachycaulus ssp. teslinensis; Agropyron trachycaulum; Agropyron trachycaulum var. trachycaulum; Agropyron trachycaulum var.  novae-angliae
Equisetum palustre	Marsh Horsetail	SNR		G5	Historic Rediscovered
Equisetum pratense	Meadow-horsetail	S2		G5	Uncommon
Equisetum variegatum ssp. variegatum	Variegated Scouring Rush	S3		G5T5	MESA-Delisted	Equisetum variegatum ssp. variegatum
Eragrostis capillaris	Lace-grass	S2?	IND.	G5	Uncommon
Erechtites hieraciifolius var. megalocarpus	Seaside Pilewort	S2S3		G5T3	Uncommon	Erechtites hieraciifolia var. megalocarpa
Eurybia radula	Rough Aster	S1S2		G5	Uncommon	Aster radula
Fuirena pumila	Annual Umbrella-sedge	S3	3	G5	MESA-Delisted
Gentiana linearis	Narrow-leaved Gentian	S2?		G4G5	Uncommon	Gentiana saponaria var. linearis; Dasystephana linearis
Gentianella quinquefolia	Stiff Gentian	S2S3	2	G5	Uncommon	Gentiana quinquefolia
Geranium bicknellii	Bicknell's Crane's Bill	S2S3		G5	Uncommon
Geum virginianum	Virginia Avens	S2?		G5	Uncommon
Hedeoma hispida	Rough Pennyroyal	S1		G5	Introduced?	Hedeoma hispidum
Helenium autumnale	Common Sneezeweed	S3?		G5	Uncommon
Heteranthera dubia	Water Star-grass	S2S3		G5	Uncommon	Zosterella dubia
Homalosorus pycnocarpos	Glade Fern	S3		G5	1985: MESA-Delisted	Athyrium pycnocarpon; Diplazium pycnocarpon; Asplenium pycnocarpon; Diplaziopsis pycnocarpa
Hottonia inflata	Featherfoil	S3		G4	Uncommon
Hypopitys lanuginosa	Hairy Pine-sap	SNR		G5	Uncommon?	Monotropa lanuginosa
Iris prismatica	Slender blue flag	SNR		G4	Uncommon	Limniris prismatica
Isotria verticillata	Large Whorled Pogonia	S3S4		G5	MESA-Delisted
Juglans cinerea	Butternut	S4?	IND.	G3	Uncommon
Juncus ambiguus	Seaside Toad-rush	S1?		G5	Historic Rediscovered	Juncus bufonius var. halophilus; Juncus bufonius var. ranarius; Juncus ranarius
Juncus nodosus	Knotted Rush	SNR		G5	Uncommon
Juncus torreyi	Torrey's Rush	SNR	2	G5	Introduced?
Juniperus horizontalis	Prostrate Juniper	SNR		G5	Introduced?
Lactuca hirsuta	Hairy Wild Lettuce	S2S3		G5?	Uncommon
Lathyrus palustris	Vetchling, Marsh-pea	SNR		G5	Uncommon
Lechea minor	Thyme-leaf Pinweed	S2S3	IND.	G5	Uncommon
Leptoloma cognata	Fall Witch-grass	SNR		G5	Introduced?	Digitaria cognata ssp. cognata; Leptoloma cognatum var. cognatum; Leptoloma cognatum; Digitaria cognata; Digitaria cognata var. cognata
Lespedeza angustifolia	Narrow-leaved Bush-clover	S3?		G4	Uncommon
Lespedeza frutescens	Violet Bush-clover	S3		G5	MESA-Delisted	Lespedeza violacea
Lespedeza stuevei		S1	IND.	G4?	Historic Rediscovered
Lilaeopsis chinensis	Lilaeopsis	S2?		G5	Uncommon
Limosella australis	Atlantic Mudwort	SNR		G5	Uncommon	Limosella aquatica var. tenuifolia
Linum intercursum	Sandplain Flax	S3		G4	MESA-Delisted
Linum striatum	Panicled Yellow Flax, Ridgestem Yellow Flax	S2S3		G5	Uncommon
Lobelia kalmii	Brook-lobelia	S2S3		G5	Uncommon
Lonicera sempervirens	Trumpet Honeysuckle	SNR		G5	Introduced?
Lonicera villosa	Mountain Fly-honeysuckle	SNR		G5	Uncommon?	Lonicera caerulea var. villosa
Luzula bulbosa	Bulbous Wood-rush	S2?		G5	Uncommon	Luzula multiflora var. bulbosa; Luzula campestris var. bulbosa
Luzula multiflora ssp. frigida	Boreal Wood-rush	SNR		G5T5	Uncommon
Lycopus amplectens	Sessile Water-horehound	S2S3		G5	Uncommon
Maianthemum trifolium	Three-leaved Solomon's Seal	S3?		G5	Uncommon	Smilacina trifolia
Menispermum canadense	Moonseed	S3		G5	Uncommon
Myriophyllum sibiricum	Northern Water-milfoil	S1S2		G5	Uncommon	Myriophyllum exalbescens
Nabalus albus	White Lettuce	SNR		G5	Uncommon	Nabalus albus
Orthilia secunda	One-sided Pyrola/One-sided Wintergreen	SNR		G5	Uncommon	Pyrola secunda; Orthilia secunda var. secunda
Panicum tuckermanii	Tuckerman's Panic-grass	SNR		G3G5	Taxonomic question	Panicum philadelphicum var. tuckermanii
Parietaria pensylvanica	Rock-pellitory	S2S3		G5	Uncommon
Paronychia fastigiata var. fastigiata	Hairy Forked Chickweed	SNR		G5T5	Introduced?
Paspalum setaceum var. psammophilum	Sand Bead-grass	S2S3	2	G5T4?	Uncommon
Paspalum setaceum var. setaceum	Small Fruited Bead-grass or Slender Bead-grass	S3?		G5T5	Uncommon
Pellaea atropurpurea	Purple Cliff-brake	S3		G5	MESA-Delisted
Phragmites australis ssp. americanus	Phragmites, North American Reed	S3		G5T5	Uncommon	Phragmites americanus
Pinus resinosa	Red Pine	S2S3		G5	Uncommon
Piptochaetium avenaceum	Black Oatgrass	SNR		G5	Uncommon	Stipa avenacea
Platanthera aquilonis	North Wind Bog Orchid	S3S4		G5	Uncommon	Limnorchis aquilonis
Platanthera blephariglottis	White-fringed Orchid	SNR		G5	Uncommon	Habenaria blephariglottis
Platanthera grandiflora	Large Purple-fringed Orchid	S4		G5	Decreasing	Platanthera grandifolia; Habenaria fimbriata; Habenaria grandiflora
Platanthera huronensis	Northern Green Orchid	S2?		G5T5?	Uncommon	Platanthera huronensis; Limnorchis huronensis
Podophyllum peltatum	May-apple	SNR	2	G5	Introduced?
Podostemum ceratophyllum	Threadfoot	S2		G4	MESA-Delisted
Polygala nuttallii	Nuttall's Milkwort	S3		G4	MESA-Delisted
Polygala verticillata	Whorled Milkwort	S2S3	IND.	G5	Uncommon
Polygala verticillata var. ambigua	Alternate Milkwort	SNR	2	G5T5?	Historic Rediscovered	Polygala ambigua
Polygonum tenue	Rock Knotweed	S2S3		G5	Uncommon	Duravia sp. 2
Populus balsamifera ssp. balsamifera	Balsam-poplar	S2S3		G5T5	Uncommon	Populus balsamifera; Populus balsamifera var. balsamifera; Populus tacamahacca
Potamogeton gemmiparus	Tiny Pondweed	S2?	IND.	G5T2	Uncommon?	Potamogeton pusillus var. gemmiparus; Potamogeton gemmiparus; Potamogeton berchtoldii ssp. gemmiparus
Potamogeton obtusifolius	Blunt-leaved Pondweed	S1?		G5	Uncommon
Pseudognaphalium macounii	Clammy Everlasting	S1S2		G5	Uncommon	Gnaphalium macounii; Gnaphalium decurrens
Pteridium aquilinum ssp. pseudocaudatum	Pine Barrens Braken	SNR		G5T5	Uncommon	Pteridium aquilinum ssp. pseudocaudatum; Pteridium latiusculum var. pseudocaudatum; Pteridium pseudocaudatum
Quercus stellata	Post Oak	S3S4		G5	MESA-Delisted
Ranunculus allegheniensis	Allegheny Buttercup	S2?	2	G4	Uncommon
Ranunculus fascicularis	Early Buttercup	S2?		G5	Uncommon
Rhododendron periclymenoides	Pinxter-flower	S2?		G5	Uncommon	Rhododendron nudiflorum var. nudiflorum; Rhododendron nudiflorum
Ribes americanum	Wild Black Currant	S3S4		G5	MESA-Delisted
Ribes rotundifolium	Round-leaved Gooseberry	S1?	IND.	G5	Uncommon
Ribes triste	Swamp Red Currant	S3		G5	MESA-Delisted
Rosa blanda	Smooth Rose	S2S3		G5	Uncommon
Rubus cuneifolius	Sand-blackberry	S1S2	2	G5	Uncommon
Rumex hastatulus	Dune-sorrel	SNR		G5	Introduced?
Sagina decumbens ssp. decumbens	Trailing Pearlwort	SNR		G5T5	Introduced?
Sagittaria rigida	Mud Arrowhead	S2?		G5	Uncommon
Salix candida	Hoary Willow	S3		G5	MESA-Delisted
Salix pedicellaris	Bog Willow	S2?		G5	Uncommon
Salix serissima	Autumn Willow	S3		G5	MESA-Delisted
Sanguisorba canadensis	Canada Burnet	SNR		G5	Uncommon	Sanguisorba canadensis ssp. canadensis
Sanicula trifoliata	Trefoil Sanicle	S2S3		G4	Uncommon
Schoenoplectus acutus var. acutus	Hard-stemmed Bulrush	S2S3		G5T5	Uncommon	Scirpus acutus; Schoenoplectus acutus
Schoenoplectus torreyi	Torrey's Bulrush	S2?		G4	Uncommon	Scirpus torreyi
Scirpus pendulus	Pendulous Bulrush	S3		G5	MESA-Delisted
Scirpus polyphyllus	Appalachian Bulrush	S2?	2	G5?	Uncommon
Scleria reticularis	Pondshore Nut-sedge	S3	1	G4	MESA-Delisted	Scleria reticularis var. reticularis
Scutellaria parvula var. missouriensis	Small Skullcap	SNR	2	G5T5	Introduced?	Scutellaria leonardii; Scutellaria parvula var. leonardii
Sedum ternatum	Mountain-stonecrop	SNR		G5	Introduced?
Selaginella rupestris	Rock Spikemoss	S3S4		G5	MESA-Delisted	Bryodesma rupestre
Sesuvium maritimum	Annual Sea-purslane	S1	2	G5	Newly Discovered
Silene caroliniana ssp. pensylvanica	Wild Pink	S2S3		G5T4	Uncommon	Silene caroliniana var. pensylvanica; Silene pensylvanica
Solidago hispida	Hispid Goldenrod	S1		G5	Historic Rediscovered
Solidago speciosa var. speciosa	Showy Goldenrod	S2S3		G5T5	Uncommon	Solidago speciosa ssp. speciosa var. speciosa; Solidago speciosa
Sparganium androcladum	Shining Bur-reed	S3?		G4G5	Uncommon
Sparganium angustifolium	Narrow-leaved Bull-reed	S2S3		G5	Uncommon
Sparganium fluctuans	Floating Bur-reed	S2S3		G5	Uncommon
Spiranthes lucida	Shining or Wide-leaved Ladies'-tresses	S2?		G4	Uncommon
Spiranthes tuberosa	Little Ladies'-tresses	S3S4		G5	MESA-Delisted
Sporobolus compositus var. compositus	Tall Dropseed	SNR		G5T5	Introduced?
Sporobolus cryptandrus	Sand Dropseed	S2?		G5	Uncommon
Stachys hyssopifolia	Hyssop Hedge-nettle	S3S4		G4G5	MESA-Delisted
Stellaria borealis ssp. borealis	Northern Starwort	S2S3		G5T5	Uncommon	Stellaria calycantha sensu lato; Stellaria borealis var. borealis
Streptopus amplexifolius	Clasping-leaf Twisted-stalk	S3?		G5	MESA-Delisted
Suaeda maritima ssp. richii	Rich's Sea-blite	S2S3	IND.	G5T3	MESA-Delisted	Suaeda richii
Symphyotrichum praealtum	Willow Aster	S1	2	G5	Historic Rediscovered	Aster praealtus
Symphyotrichum prenanthoides	Crooked-stem Aster	S2	2	G5	MESA-Delisted	Aster prenanthoides
Tephrosia virginiana	Goat's Rue	SNR		G5	Uncommon
Utricularia minor	Lesser Bladderwort	S2S3		G5	Uncommon
Uvularia grandiflora	Large-flowered Bellwort	S3		G5	MESA-Delisted
Veronica serpyllifolia ssp. humifusa	Northern Thyme-leaf Speedwell	SNR		G5T5	Introduced?	Veronica serpyllifolia var. humifusa
Viola renifolia	Kidney-leaf Violet	S1S2		G5	Uncommon
Viola rostrata	Long-spurred Violet	S2S3		G5	Uncommon
Viola selkirkii	Great-spurred Violet	S1S2		G5	Uncommon
Viola subsinuata	Early Blue Violet	S1S2	IND.	G4	Uncommon	Viola subsinuata var. subsinuata; Viola emarginata var. subsinuata
Wolffia borealis	Northern Water-meal	SNR		G5	Uncommon
Wolffiella gladiata	Sickle Water-meal	SNR	2	G4G5	Uncommon	Wolffiella floridana
Xyris montana	Northern Yellow-eyed Grass	S2?		G5	Uncommon
Xyris smalliana	Quagmire Yellow-eyed grass	S4		G4G5	Uncommon?	Xyris congdonii
Zizania palustris var. palustris	Slender Wild Rice	S1S2		G5T4	Uncommon	Zizania aquatica var. angustifolia

Last updated:	February 10, 2025