Helianthemum canadense (Longbranch frostweed)

Helianthemum canadense (L.) Michx.

Crocanthemum canadense (L.) Britton

Helianthemum canadense (L.) Michx. var. sabulonum Fernald

Longbranch frostweed

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Rosidae	Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
Order	Malvales	Includes cacao, balsa, lime, linden, basswood, daphnes, hibiscus, hollyhocks, okra, baobab, cotton, kapok, and many others
Family	Cistaceae
Genus	Helianthemum	From the Greek helios, “sun,” and anthemon, “flower,” because the flowers open only in the sun
Species	canadense	“Of or from Canada”

About plant names...

Helianthemum means roughly “sunflower,” from the Greek Ἥλιος (helios), or sun, and ανθέμιον (anthemion), or flower. These plants are native to North America.

Identification: Plants are 8-24" (20-60 cm) tall, branching from a single stem to multiple branches when mature, with the new branches larger than the original. Leaves are alternate, narrow, tapered at both ends. Flowers are bright yellow, with five overlapping petals, ⅝-1" (1.7-2.9 cm) in diameter. Flowers appear from May to June.

Online References:

Helianthemum canadense at the University of Wisconsin's Robert W. Freckmann Herbarium

Helianthemum canadense on Plants for a Future, a resource and information centre for edible and otherwise useful plants

Helianthemum canadense on www.pbase.com

Helianthemum canadense at the Lady Bird Johnson Wildflower Center

5/25/2010 · Nashua River Rail Trail, Ayer, Massachusetts
≈ 3½ × 6" (9.7 × 15 cm) ID is uncertain

6/1/2012 · Pearl Hill State Park, Townsend, Massachusetts
≈ 4 × 4½" (10 × 11 cm)

5/25/2010 · Nashua River Rail Trail, Ayer, Massachusetts
≈ 2½ × 2½" (6.7 × 6.2 cm) ID is uncertain

6/2/2016 · Townsend Wildlife Management Area, Townsend, Massachusetts

Helianthemum canadense description by Thomas H. Kent, last updated 25 May 2020.

6/2/2016 · Townsend Wildlife Management Area, Townsend, Massachusetts

6/1/2012 · Pearl Hill State Park, Townsend, Massachusetts
≈ 7 × 4½" (16 × 11 cm)

6/1/2012 · Pearl Hill State Park, Townsend, Massachusetts
≈ 4½ × 5" (11 × 12 cm)

6/22/2010 · Nashua River Rail Trail, Ayer, Massachusetts
≈ 7 × 4½" (17 × 11 cm)

6/2/2016 · Townsend Wildlife Management Area, Townsend, Massachusetts

6/21/2017 · Pearl Hill State Park, Townsend, Massachusetts
≈ 3½ × 6" (9.4 × 14 cm)

6/2/2016 · Townsend Wildlife Management Are, Townsend, Massachusetts

Range:

About this map...