Recognition of Winter Annuals – Part 2

The purpose of Part 2 is to provide additional information about the plants introduced in Part 1, and in most cases, to  illustrate their mature form.  Some of the plants change form completely while others change very little from their winter appearance

Galium sherardia (Blue Field Madder)

Blue Field Madder is not a native species, but was introduced from Eurasia.  Often better known as Sherardia arvensis, the previous scientific name, it is a member of the Bedstraw family (the Rubiaceae), and like most of its close relatives, is not particularly invasive.  It is hard to find isolated individuals like those shown below; it is usually tangled with other vegetation, and can form large mats, like those pictured in the second photograph.

Galium sherardia
Blue Field Madder
Winter Appearance

 

Galium sherardia
Blue Field Madder
Multiple Plants

Blue Field Madder is easy to distinguish from the other bedstraws by its blue flowers and sharply pointed leaves.  The tiny flowers, shown below, resemble those of the early spring Bluets, which are close relatives.

Galium sherardia
Blue Field Madder
Flowers

Nuttallanthus canadensis – Blue Toadflax

 Blue Toadflax is a true native wildflower, and one of the most prolific in the Southeast.  It can be seen blooming in early to mid spring by the thousands in fields and roadsides.  In winter it resembles a tiny portulaca , but as spring approaches, the plant form changes.  Tall, stringy stems are produced, followed by small, blue flowers at the tips.  The sequential changes are summarized in the photos below.

Nuttallanthus canadensis
Blue Toadflax
Winter Appearance

 

Nuttallanthus canadensis
Blue Toadflax
Early Spring

 

Nuttallanthus canadensis
Blue Toadflax
Maturing Plant

 

Nuttallanthus canadensis
Blue Toadflax
Flowers

Scleranthus annuus – Knawel

Knawel is an introduced species from Eurasia that has become a major weed of lawns, grassy parks, and roadsides.  The leaves are linear and needle-like, with stiff points, somewhat resembling the leaves of a creeping phlox.  Knawel is actually related to carnations in the Caryophyllaceae family.

Scleranthus annuus
Knawel
Winter Plant Form

The flower, pictured below, has no petals, but has 5 green sepals, which give the appearance of petals.

Scleranthus annuus
Knawel
Flower

Soliva sessilis – Burweed

Burweed is another non-native plant, introduced from South America.  Like Knawel, it is a troublesome weed of lawns and roadsides.  In fact the two plants are very often found together.    Burweed is hard on bare feet as it produces seeds in the leaf axils that have durable, vertical, spine tips that remain upright.  It is a very unpopular lawn weed.

Soliva sessilis
Burweed
Plant Form

Erigeron annuus – Annual Fleabane

Annual Fleabane is a native, and one of the commonest and best known late spring wildflowers.  It is found along roadsides, greenways, in open fields and disturbed areas.  It is often referred to as the spring daisy, and Daisy Fleabane is a common name given to this plant along with other closely related fleabanes.  The leaves along the flowering stem are very similar to the basal leaves shown below.

Erigeron annuus
Annual Fleabane
Basal Leaves

Annual Fleabane can be distinguished from the asters due to its earlier flowering and its higher number of narrow petals.

Erigeron annuus
Annual Fleabane
Flowers

Lobelia inflata – Indian Tobacco

Lobelia inflata is a summer annual with a long bloom time, extending from the summer into late fall.  The odd common name comes from the historic use of this plant by Native Americans for a variety of purposes.  It has a scent reminiscent of tobacco, hence the origin of the name.  Lobelia inflata is a prolific seeder.  When leaf litter is low, and a good amount of soil is exposed, a single plant can produce 50 or more seedling rosettes similar to the one pictured below.

Lobelia inflata
Indian Tobacco
Basal Leaves

The flowers are small but have the typical appearance of Lobelia flowers, with two petals up and three petals down.  The species name “inflata” comes from the balloon-like appearance of the seed pods.  One can be seen in the photograph below, under the bloom and out of focus.

Lobelia inflata
Indian Tobacco
Flower and Seed Pod

 

Herb Amyx

 

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