Weed Identification

1
Weed Identification
Andrew Senesac, Cornell Co-op Extension Marilyn
Jordan, The Nature Conservancy
2
Online Information Sources for Plant
Identification
http//plants.usda.gov/ National Plants
Database USDA, NRCS. Species photos and keys to
taxonomic groups http//www.ct.nrcs.usda.gov/inva
s-factsheets.html Connecticut NRCS http//tncweed
s.ucdavis.edu./esadocs.html The Nature
Conservancy http//www.bbg.org/sci/nymf/key/index
.html Brooklyn Botanic Garden key to woody
plants http//www.state.ma.us/dem/programs/lakepo
nd/ aquatic_species.pdf Download aquatic
species guide (See handout, page 3 of complete
weed list)
3
Mitchell, R. S. and G. C. Tucker. 1997. Revised
Checklist of New York State Plants. Bulletin
490. The University of the State of New York.
The State Education Department. Albany, NY
12230 http//www.nysm.nysed.gov/publications/biopu
b.html
Uva, R., J. C. Neal and D. J. M. DiTomaso.
1997. Weeds of the Northeast. Comstock
Publishing Assoc., a division of Cornell
University Press, Ithaca N.Y.

(includes native species)
See handout, reference list
4
Mitchell Tucker indicates species not
native to New York
5
REPORT ANYWHERE ON LONG ISLAND New
Invaders Land Wetlands 631-367-3384 ext. 108
6
KudzuPueria montana var. lobata (PUMO)

• Semi-woody perennial vine to 100 ft.
• Leaves 4-6 inches long with 3 leaflets (which
  may be lobed), hairy beneath.
• Flowers reddish purple, grape- scented.
• vine kills native vegetation by shading,
  girdling or uprooting by its own weight.

Habit
Flowers
7
Black Swallow-wortCynanchum louiseae (CYLO)
flowers
TNC
Seed pod
leaves
Young
8
Mile-A-Minute Weed / VinePolygonum perfoliatum
(POPE)
Habitat
Senesac
Jordan
Fruit
Ocrea
Leaves
Hyatt
Jordan
9
Purple LoosestrifeLythrum salicaria (LYSA)
TNC
Mehrhoff
10
Giant hogweed/ Cow parsnipHeracleum
mantegazziamum (HEMA)

• Herbaceous biennial or perennial up to 15 feet
  tall.
• Leaves deeply lobed
• Stem purple-blotched
• Rays of the umbel flower head 50-150.
• Poisonous - causes painful blisters on human
  skin, UV sensitivity, and blindness.

Leaf
Jordan
Umbel inflorescence
11
Chinese yamDioscorea oppositifolia (DIOP)

• Herbaceous perennial
• vines twine from the left to the right
• New leaves often have a bronze 'tint'

Potato
Leaves
Flowers
12
Tall PepperweedLepidium latifolium (LELA)
Flowers
Basal Rosettes
13
Narrowleaf bittercress Cardamine impatiens (CAIM)


Stem Morphology
Auriculate leaf base
petiole
Inflorescence
stem
Basal Rosette
14
CottonweedFroelichia gracilis (FRGR)
habitat
flowers
15
Japanese hopsHumulus japonicus (HUJA)
Leafy Plant
Inconspicuous flowers
Shiny Leaves
16
Chinese lobeliaLobelia chinensis

• Perennial
• Medicinal herb from asia
• Confirmed sighting in Pennsylvania
• Lake and river banks

17
REPORT ANYWHERE ON LONG ISLAND New
Invaders Aquatic 631-367-3384 ext. 108
18
Water chestnutTrapa natans (TRNA)

• aquatic annual that grows as a rooted, floating
  plant
• floating leaves are arranged in a rosette
• thorny black nutlets with terminal barbs
• inconspicuous white flowers in the center of the
  rosette
• forms surface mats- which causes competition for
  nutrients and space

Leaves
Rosettes
19
Eurasian water milfoilMyriophyllum spicatum L.
(MYSP)

• Herbaceous perennial
• rooted submersed herb with long branching stems
  and feather-like whorled leaves its small
  reddish flowers are held above the water on a
  spike swimmers become entangled in dense stands
  of the plant
• Largely displaces existing native plants
• stems can "top out" in 20 feet of water

Habitat
Flower
Leaves
20
European frog-bitHydrocharis morsus-ranae (HYMO)
White flower
habitat
21
HydrillaHydrilla verticillata (HYVE)

• herbaceous perennial
• plant is noticeably rough to the touch when
  pulled through the hand
• invisible until it fills the lake or river that
  it infests, "topping out" at the surface
• ecologically-important native submersed plants
  shaded out by hydrilla's thick mats, or are
  outcompeted or eliminated
• considered the most problematic aquatic plant in
  the United States

Whorls of five leaves
22
MudmatGlossostigma diandrum

• unusual, bright green patches on muddy substrates
  of freshwater littoral zones in full sun.
• closely resembles native Limosella (mudwort)
• minute, bell-shaped, pastel colored flowers
  produced on short stalks in summer.
• Closed, self-fertilizing flowers, also produced
  underwater and in the soil

23
Floating Primrose-Willow
Ludwigia peploides (Kunth) Raven

• An aquatic perennial herb
• The stems sprawl or grow horizontally on water or
  mud
• The leaves are alternate and simple
• the flowers are bright yellow with 5 pedals

Jacobs
Senesac
Senesac
Jacobs

• At flowering the leaves lengthen to a
  willow-like, elliptic shape.

• The seeds are ellipsoid, yellowish, shorter than
  1 mm

Senesac
Senesac
24
Brazilian Water Weed

• Egeria densa Planchon

• Underwater plant with very dark green leaves, up
  to 4cm long, in whorls of four to six.
• Leaves are abruptly narrowed to a pointed tip,
  very fine teeth on leaf edges require a hand lens
  to see.
• Buoyant, slender stems are usually 1-2 feet long
  with nodes becoming closer towards the stem tip.

Rice, TNC

• White flowers protrude just above the surface,
  with three petals 4-12 mm long and nine golden
  stamens.
• A popular species for aquarium use.
• Only male plants are found in the U.S.

25
Nymphoides peltataYellow floating heart
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REPORT ONLY IN PRESERVES AND NATURAL
AREASCOMMON SPECIES
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Norway MapleAcer platanoides L.

• Commonly planted street tree, invades woodlands
  forests
• Leaves 4-7 inches wide 5-7 pointed lobes
• Leaf petiole exudes white sap when broken
• Seed wings diverge 180
• Flowers yellow-green, appear in April-May
• Bark grayish, shallowly grooved

bark
28
Tree of Heaven Ailanthus altissima (Miller)
Swingle

• Fast-growing tree, often in groups
• Leaflets in pairs along central stalk, with
  single, terminal leaflet with one or more coarse
  teeth at base and large gland beneath each tooth
• Stout twigs with heart-shaped leaf scars
• Each seed in center of long, twisting wing
• Male female flowers on separate trees

J. Randall
C. Bargeron 1150028
29
Japanese KnotweedPolygonum cuspidatum Sieb.
Zucc.

• Aggressive perennial, forms thickets 3-6 ft tall
• Stems hollow, jointed, bamboo-like
• Leaves alternate, 3-6 inches long, leathery
• Flowers greenish white
• Grows in wetlands and uplands, especially
  troublesome along streams.

M. Jordan
J. Randall
30
JetbeadRhodotypos scandens (RHSC)
Fruit
Flower
M. Jordan
31
Buckthorn Rhamnus frangula R. cathartica
Mohlenbrock USDA NRCS
Mehrhoff
R. frangula (Frangula alnus)
Mehrhoff
USDA-NRCS PLANTS Database / Britton, N.L., and A.
Brown 1913
32
Japanese Barberry Berberis thunbegii DC

• Deciduous shrub 0.5-2.4 m (2-8 ft.) high
• Branches deeply grooved, brown, usually have
  spines.
• Bright red berries.

Japanese barberry
Common barberrry (B. vulgaris) IPANE
33
Bush Honeysuckle Lonicera tartarica/bella/morrowi
i/maackii

• woody perennial shrubs.
• Opposite leaves.
• twigs have hollow stems, while stems of native
  species are solid.
• Paired flowers.
• Red berries.

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Multiflora roseRosa multiflora Thunb. ex Murr.

• Densely spreading perennial shrub.
• Arching canes red to green in color, glabrous (no
  hairs) with recurved thorns.
• Leaves alternate, pinnately compound, 5 - 11
  serrated leaflets (1-1.5in.) long smooth and
  dark above, pale with small hairs below.
• Feathery or comb-like margin on its stipules

TNC
35
Chocolate VineAkebia quinata Houtt
Ornamental vine, 5 leaflets
36
Garlic MustardAlliaria petiolata (Bieb.) Cav.
Grande

• Herbaceous biennial first year plants a rosette,
  mature flowering plant reaches 3.3 feet in height
  in year two
• Flowers in April flowers with four white petals
  narrow pods in May with shiny black seeds 0.1
  inch
• Leaves coarsely toothed lower leaves
  kidney-shaped stem leaves deltoid in shape
  leaves smell of garlic when crushed

rosette
Seed pods
M. Jordan
J. Randall
37
Lesser celandine (fig buttercup) Ranunculus
ficaria (RAFI)
flowers
habitat
38
Chinese Silver GrassMiscanthus sinensis (MISI)
M. Jordan
M. Jordan
J. Gallagher
39
Japanese stilt grass Microstegium vimineum
M. Jordan

• Prostrate annual grass, roots at the nodes
• Nodes glabrous (smooth)
• Light green leaves with a silvery line down the
  center
• Flowers in mid-September
• Inflorescence a terminal, thick-branched panicle
• Lemma awned or awnless

J. Ehrenfeld
M. Jordan
40
Cypress spurge Euphorbia cyparissias

• Similar to leafy spurge, but shorter (15-30 cm
  tall), narrower leaves (1-3 mm wide)
• Exudes milky sap when injured.
• The (fertile) tetraploid form is much more
  vigorous and weedy than the (sterile) diploid
  form.

41
Mugwort Artemisia vulgaris L.

• Perennial, stems woody, up to 5 feet tall.
• Underground rhizomes.
• Leaves deeply lobed (especially on upper part of
  plant) with a distinctive aroma.
• Leaf undersides covered with soft, white to gray
  hairs upper surfaces smooth to slightly hairy.

M. Jordan
M. Jordan
M. Jordan
M. Jordan
Ragweed Mugwort (native)
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COMMON SPECIES TO ADD TO SLIDEHOW Autumn olive,
bentgrass, Black locust, Cabomba, Chinese
lespedeza, Common Reed, Japanese honeysuckle,
Oriental bittersweet, Porcelain-berry, Spotted
knapweed. Add to common list? report in
preserves? Cabomba caroliniana, Ceratophyllum
demersum, Pomogeton crispus L., Autumn (yam-leaf)
clematis. Winged Euonymus. Add to report
anywhere list, (Aquatic) Callitriche stagnalis
Scop. (water chickweed), Egeria densa Planchon
(Brazilian water weed)-done by Brian Henry