Atlas of the Flora of New England

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Genera - I

Inula (see also Dittrichia)
Isanthus (see Trichostema)
Iva (see also Cyclachaena)

IBERIS (Family: Brassicaceae)

IBERIS AMARA Linnaeus - Rocket Candytuft. 2n = 14, 28.

Waste places, especially dumps. From western Europe.

IBERIS SEMPERVIRENS Linnaeus - Evergreen Candytuft. 2n = 22, (66).

Fields, waste places. From Europe.

IBERIS UMBELLATA Linnaeus - Globe Candytuft. 2n = 14, 16, 18, 34.

Waste places. From Europe.

ILEX (Family: Aquifoliaceae)

ILEX CRENATA Thunberg - Japanese Holly. 2n = 34.

Dry, oak woodland margins, thickets. From eastern Asia.

Ilex glabra (Linnaeus) A. Gray - Inkberry. 2n = ?

Swamps, wet woods, low sandy or peaty soil.

Ilex laevigata (Pursh) A. Gray - Smooth Winterberry. 2n = ?

Swamps, wet woods, thickets.

Ilex ambigua (Michaux) Torrey var. monticola (A. Gray) Wunderlin & Poppleton - . 2n = 40.

Rich wooded slopes and mountainsides. [I. montana Torrey & A. Gray]

Ilex mucronata (Linnaeus) M. Powell, Savolainen, & S. Andrews - Mountain-holly. 2n = 40.

Swamps, bogs, damp thickets, cool, damp woods. [Nemopanthus mucronatus (Linnaeus) Trelease ex Loesener]

Ilex opaca Aiton var. opaca - American Holly. 2n = 36.

Moist, often sandy, woods, dune hollows, swamps and swamp margins.

Ilex verticillata (Linnaeus) A. Gray - Common Winterberry. 2n = 36, 72.

Swamps, damp thickets, wet woods, pond margins. [I. verticillata var. cyclophylla B.L. Robinson; I. verticillata var. fastigiata (E.P. Bicknell) Fernald; I. verticillata var. padifolia (Willdenow) Torrey & A. Gray ex S. Watson; I. verticillata var. tenuifolia (Torrey) S. Watson]

IMPATIENS (Family: Balsaminaceae)

IMPATIENS BALSAMINA Linnaeus - Garden Balsam. 2n = (12), 14, (18), (28), (56).

Waste places, beaches. From southern Asia.

Impatiens capensis Meerburgh - Spotted Touch-me-not. 2n = 20.

Swamps, springy places, brooksides, wet, roadside ditches, moist, shady soil.


Waste places, roadsides, in rich soil. From Indian subcontinent.

Impatiens pallida Nuttall - Pale Touch-me-not. 2n = 20, 30.

Springy places, wet, deciduous woodlands, moist, shady, chiefly calcareous soil.

INULA (Family: Asteraceae)

INULA HELENIUM Linnaeus - Elecampane. 2n = 20.

Damp fields, roadsides, clearings, waste places. From Eurasia.

INULA RACEMOSA Hooker (son) - 2n = 20.

Open, disturbed ground. From central Asia.

IONACTIS (Family: Asteraceae)

Ionactis linariifolia (Linnaeus) Greene - Stiff Aster. 2n = 18.

Dry, open, sandy soil, woods borders, rocky outcrops. [Aster linariifolius Linnaeus]

IPOMOEA (Family: Convolvulaceae)

IPOMOEA COCCINEA Linnaeus - Red Morning-glory. 2n = 28.

Thickets, roadsides, waste places. From farther south.

IPOMOEA HEDERACEA Jacquin - . 2n = 30.

Fields, pond shores, roadsides, waste places. From Mexico, Central America, western South America, Caribbean. [I. HIRSUTULA misapplied]

IPOMOEA HEDERIFOLIA Linnaeus - Scarlet Creeper. 2n = 28.

Roadsides, waste places. From farther south, Central and South America, Caribbean.

IPOMOEA LACUNOSA Linnaeus - White Morning-glory. 2n = 30.

Waste places, railroads. From farther south and west,

Ipomoea pandurata (Linnaeus) G. Meyer - Wild Potato-vine. 2n = 30.

Dry fields.

IPOMOEA PURPUREA (Linnaeus) Roth - Common Morning-glory. 2n = 30, (32).

Roadsides, field margins, waste places. From tropical America. [I. HIRSUTULA J. Jacquin]

IPOMOPSIS (Family: Polemoniaceae)

IPOMOPSIS RUBRA (Linnaeus) Wherry - Standing-cypress. 2n = 14.

Sandy soil. From farther south and west. [GILIA RUBRA (Linnaeus) A. Heller]

IRIS (Family: Iridaceae)

IRIS CRISTATA Aiton - Dwarf Crested Iris. 2n = 24, 32.

Rich woods, in acid soils. From farther south and west.

IRIS DOMESTICA (Linnaeus) Goldblatt & Mabberley - . 2n = (16), (27), (28), (30), 32, (128).

Fields, roadsides, thickets, open woods. From eastern Asia. [BELAMCANDA CHINENSIS (Linnaeus) Redouté]

IRIS GERMANICA Linnaeus - Fleur-de-lis. 2n = (24), (28), 44, 48.

Roadsides, waste places. From Europe.

Iris prismatica Pursh ex Ker Gawler - Slender Blue Flag. 2n = 42.

Marshes, meadows, swamps, sands, shores, seacoasts.

IRIS PSEUDACORUS Linnaeus - Yellow Iris. 2n = (24), (32), 34.

Swamps, wet meadows, marshes, brooksides, waste places. From Europe.

IRIS PUMILA Linnaeus subsp. PUMILA - . 2n = (20), (24), (30), 32, (36).

Dry, rocky knolls. From Eurasia.

Iris setosa Pallas ex Link - Beachhead Iris. 2n = (36), 38.

Rocky slopes, upper borders of beaches, moist fields, always near salt water. [I. hookeri Penny ex G. Don]

IRIS SIBIRICA Linnaeus - Siberian Iris. 2n = 28.

Wet meadows, waste lots. From Eurasia.

IRIS TECTORUM Maximowicz - Wall Iris. 2n = 28, (32), (36).

Habitat? From China.

Iris versicolor Linnaeus - Blue Flag. 2n = 108.

Swamps, marshes, meadows, shores, ditches.

Iris hybrid

Iris prismatica Pursh ex Ker Gawler X Iris versicolor Linnaeus - .

ISATIS (Family: Brassicaceae)

ISATIS TINCTORIA Linnaeus - Dyer’s Woad. 2n = (14), 28.

Roadsides, fields, waste places. From Eurasia, northern Africa.

ISOËTES (Family: Isoëtaceae)

Isoëtes acadiensis Kott - Acadian Quillwort. 2n = (22), 44.

Shallow water of ponds and slow moving streams. [The report of 2n = 44 (Kott and Britton 1980) for I. macrospora Durieu forma hieroglyphica (A. A. Eaton) N. E. Pfeiffer was later attributed (Kott 1981) to I. acadiensis).]   CONN herbarium image

Isoëtes echinospora Durieu - Braun's Quillwort. 2n = 22, (33).

Shallow water and shores of slightly acidic lakes, ponds, and streams. [I. echinospora var. braunii (Durieu) Engelmann; I. echinospora var. muricata (Durieu) Engelmann; I. muricata Durieu]    CONN herbarium image

Isoëtes engelmannii A. Braun - Engelmann's Quillwort. 2n = 22, (44).

Shallow water of ponds, lakes, streams, or in muddy ditches.    CONN herbarium image

Isoëtes lacustris Linnaeus - Lake Quillwort. 2n = 110.

Shores and shallow water of slightly acidic ponds, lakes, and streams. [I. macrospora Durieu; I. hieroglyphica A.A. Eaton]    CONN herbarium image

Isoëtes prototypus D.M. Britton - . 2n = 22.

Deep water of cold, acidic lakes. CONN herbarium image

Isoëtes riparia Engelmann ex A. Braun - Riverbank Quillwort. 2n = 44.

Muddy or sandy shores (including tidal shores and estuaries), usually of rivers. [I. riparia var. canadensis Engelmann; I. saccharata Engelmann var. amesii A.A. Eaton]    CONN herbarium image

Isoëtes tuckermanii A. Braun ex Engelmann - Tuckerman's Quillwort. 2n = 44.

Pond and lake margins, shores (frequently tidal), usually submersed in quiet water.    CONN herbarium image

Isoëtes viridimontana M.A. Rosenthal & W.C. Taylor - . 2n = 22.

Lake margin submersed in quiet water. To date (2014) found only in Windham County, Vermont. See American Fern Journal 104; 7-15 (2014).       VT herbarium image

Isoëtes hybrids

Isoëtes x eatonii R. Dodge (pro species).

[I. echinospora Durieu X I. engelmannii A. Braun; I. gravesii A.A. Eaton]

Isoëtes x echtuckeri D.F. Brunton & D.M. Britton.

[I. echinospora Durieu X I. tuckermanii A. Braun ex Engelmann]

Isoëtes x harveyi A.A. Eaton (pro species).

[I. lacustris Linnaeus X I. tuckermanii A. Braun]   This hybrid was recognized relatively recently by Britton (1991). Herbarium specimens annotated as this hybrid are from southern Penobscot Co., Maine (US); Somerset Co., Maine (MAINE); and Mt. Desert Island, Maine (MO). Since the holdings of NEBC have not been examined critically for this hybrid, it is not mapped.

ISOTRIA (Family: Orchidaceae)

Isotria medeoloides (Pursh) Rafinesque - Small Whorled Pogonia. 2n = 18.

Open second growth, rich woods, often near Fagus.

Isotria verticillata (Muhlenberg ex Willdenow) Rafinesque - Large Whorled Pogonia. 2n = 18.

Acidic woods, usually damp, often with Medeola.

IVA (Family: Asteraceae)

IVA ANNUA Linnaeus - Sumpweed. 2n = 34.

Waste places. From farther west and south. [I. CILIATA Willdenow]

Iva frutescens Linnaeus - Jesuits’-bark. 2n = 34.

Saline marshes and shores at normal high tide limit. [I. frutescens var. oraria (Bartlett) Fernald & Griscom]

Designed by Ray Angelo. Revised Apr. 9, 2021