Atlas of the Flora of New England

Genera: A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q-R  S  T  U  V  W  X-Y-Z

Families: A  B  C  D  E  F  G  H  I  J  L  M  N  O  P  R  S  T  U  V  W-X-Z

Home     Introduction     Spreadsheets     Excluded Taxa     Bibliography     References     Useful Links

Genera - J


JACOBAEA (Family: Asteraceae)

JACOBAEA VULGARIS Gaertner - Stinking Willie. 2n = 40.

Wet pastures, roadsides. From Eurasia, northern Africa. [SENECIO JACOBAEA Linnaeus]

JASIONE (Family: Campanulaceae)

JASIONE MONTANA Linnaeus - Sheep’s-bit. 2n = 12.

Roadsides, sandy banks, fields, waste places, often in sandy soil. From Eurasia.

JUGLANS (Family: Juglandaceae)

JUGLANS AILANTIFOLIA Carrière - Japanese Walnut. 2n = 32.

Thickets, roadsides. From Japan, Sakhalin, Russia. [J. MANDSHURICA Maximowicz var. SACHALINENSIS (Miyabe & Kudo) Kitamura; J. SIEBOLDIANA Maximowicz]

Juglans cinerea Linnaeus - Butternut. 2n = 32.

Roadsides, rich woods, river terraces and valleys, rocky slopes.

Juglans nigra Linnaeus - Black Walnut. 2n = 32.

Rich woods.

JUNCUS (Family: Juncaceae)

Juncus alpinoarticulatus Chaix - Alpine Rush. 2n = 40.

Shores, meadows, usually basic. [J. alpinus Villars; J. alpinus var. fuscescens Fernald; J. alpinus var. rariflorus Hartmann]

Juncus anthelatus (Wiegand) R.E. Brooks - . 2n = 80.

Moist sandy or clay soils. [J. tenuis Willdenow var. anthelatus Wiegand]

Juncus articulatus Linnaeus - . 2n = (40), 80.

Shores, springy spots, ditches. [J. articulatus var. obtusatus Engelmann]

Juncus balticus Willdenow subsp. littoralis (Engelmann) Snogerup - Wire Rush. 2n = ?

Sandy shores, sphagnous meadows. [J. arcticus Willdenow var. balticus (Willdenow) Trautvetter]

Juncus brachycarpus Engelmann - . 2n = 44.

Salt marshes, ocean beaches.

Juncus brachycephalus (Engelmann) Buchenau - . 2n = 80.

Basic shores, marshes, meadows, swamps.

Juncus bufonius Linnaeus - Toad Rush. 2n = 80, 106, 108.

Shores, salt marshes, roadsides, moist to wet borrow pits. [J. bufonius var. halophilus Buchenau & Fernald]

Juncus canadensis J. Gay ex Laharpe - . 2n = 80.

Shores, swamps, marshes, meadows. [J. canadensis var. sparsiflorus Fernald]

JUNCUS COMPRESSUS Jacquin - . 2n = 44.

Disturbed wet ground, especially ditches, roadsides, frequently saline or basic soils. From Europe.

Juncus debilis A. Gray - . 2n = ?.

Ditches, pools, shores.

Juncus dichotomus Elliott - . 2n = ca. 80.

Sandy or sphagnous shores, salt marsh borders. [J. platyphyllus (Wiegand) Fernald; J. tenuis Willdenow var. dichotomus (Elliott) Alph. Wood]


Waste places, shores, typically in sandy, wet soil. Probably from South America.

Juncus dudleyi Wiegand - . 2n = 42, 80, ca. 84.

Shores, boggy meadows, in basic soils. [J. tenuis Willdenow var. dudleyi (Wiegand) F.J. Hermann]

Juncus effusus Linnaeus - Tufted Rush. 2n = (5), 40, 42.

Marshy ground, low spots. [J. effusus var. compactus misapplied; J. effusus var. conglomeratus (Linnaeus) Engelmann invalid name; J. effusus var. costulatus Fernald; J. effusus var. decipiens Buchenau; J. effusus var. pylaei (Laharpe) Fernald & Wiegand; J. effusus subsp. solutus (Fernald & Wiegand) H¨met-Ahti; J. effusus var. solutus Fernald & Wiegand; J. conglomeratus Linnaeus; J. pylaei Laharpe]

JUNCUS ENSIFOLIUS Wikström var. ENSIFOLIUS - . 2n = 40.

Disturbed wet ground, especially ditches, roadsides. From farther west.

Juncus filiformis Linnaeus - . 2n = (40), (70), (80), 84.

Shores, swamps, bogs, alpine meadows.

Juncus gerardii Loiseleur-Deslongchamps - Black Grass. 2n = 80, 84.

Salt marshes. [J. gerardii var. pedicellatus Fernald]

Juncus greenei Oakes & Tuckerman - . 2n = 80.

Dry, open places, usually well-drained, sandy soil. In pine lands near lake shores, dunes.

JUNCUS INFLEXUS Linnaeus - . 2n = 20, (38), 40, (80).

Meadows, damp roadsides. From Eurasia and northern Africa.

Juncus marginatus Rostkovius - Grass Rush. 2n = (38), 40.

Sandy pond margins, wet meadows. [J. biflorus Elliott]

Juncus militaris Bigelow - Bayonet Rush. 2n = ?.

Shallow water of ponds and streams with sandy, gravelly or sphagnous margins.

Juncus nodosus Linnaeus - . 2n = 40.

Shores, marshes, meadows, swamps, especially basic soils.

Juncus pelocarpus E. Meyer - . 2n = 40.

Sandy shores, marshes, ditches.

Juncus pervetus Fernald - . 2n = ?

Salt marsh borders. [J. SUBNODULOSUS Schrank misapplied] This taxon is possibly of hybrid origin. Only historical collections with aborted seeds are known.

Juncus pondii Alph. Wood - . 2n = 40.

Tidal mud flats, salt marsh borders, ditches, shores, meadows. [J. acuminatus Michaux -- invalid name]

Juncus secundus P. Beauvois ex Poiret - . 2n = ca. 80.

Ledges, dry, open, sterile soils.

Juncus stygius Linnaeus var. americanus Buchenau - . 2n = ?.

Bogs, bog pools.

Juncus subcaudatus (Engelmann) Coville & S. F. Blake - . 2n = ?.

Swamps, bogs, shaded spring-heads, mossy woods.

Juncus subtilis E. Meyer - Creeping Rush. 2n = 40.

Muddy shores.

Juncus tenuis Willdenow - Path Rush. 2n = (40), (80), 84.

Roadsides, paths. [J. tenuis var. williamsii Fernald]

JUNCUS TORREYI Coville - . 2n = 40.

Shores, ditches, roadsides. From farther west and south.

Juncus trifidus Linnaeus - Highland Rush. 2n = 30, (40).

Exposed, rocky or sterile summits. [J. trifidus var. monanthos misapplied]

Juncus tweedyi Rydberg - . 2n = 80.

Shores, bogs, marshes. [J. brevicaudatus (Engelmann) Fernald -- invalid name]

Juncus vaseyi Engelmann - . 2n = 42, ca. 80.

Swamps, shores, thickets.

JUNCUS hybrids

Juncus articulatus Linnaeus X J. tweedyi Rydberg - .

Juncus nodosus Linnaeus X J. tweedyi Rydberg - .

Juncus x oronensis Fernald (pro species) - .

Alder swamps, thickets. [J. tenuis Willdenow X J. vaseyi Engelmann ?]

Juncus secundus P. Beauvois ex Poiret X J. tenuis Willdenow - .

Juncus tenuis Willdenow X J. vaseyi Engelmann - .

JUNIPERUS (Family: Cupressaceae)

JUNIPERUS COMMUNIS Linnaeus var. COMMUNIS Pursh - Common Juniper. 2n = 22.

Woodland clearings, cemeteries. From Eurasia.

Juniperus communis Linnaeus var. depressa Pursh - Ground Juniper. 2n = 22.

Poor soils in open areas, especially old pastures and ledges, persisting in recent woodlands. [Larger individuals have been misidentified as var. COMMUNIS.]    CONN herbarium image

Juniperus horizontalis Moench - Creeping Juniper. 2n = 22.

Ledges, sandy or rocky banks.    CONN herbarium image

Juniperus virginiana Linnaeus var. virginiana - Eastern Red Cedar. 2n = 22.

Mostly dry, open sites (typically old fields), rocky slopes, borders of salt marshes, persisting in recent woodlands. [J. virginiana var. crebra Fernald & Griscom]    CONN herbarium image

Juniperus hybrids

Juniperus communis Linnaeus var. depressa Pursh X J. virginiana Linnaeus var. virginiana.

Juniperus horizontalisMoench X J. virginiana Linnaeus var. virginiana.

JUSTICIA (Family: Acanthaceae)

Justicia americana (Linnaeus) Vahl - . 2n = 26.

Margins or shallow beds of streams.

Designed by Ray Angelo. Revised June 13, 2022