Slatsz' plant photo-biography: Erigeron compositus, cut-leaf fleabane

Erigeron compositus

Native

Asteraceae family

Smithsonian – National Museum of natural History

Lewis & Clark as naturalists

http://www.mnh.si.edu/lewisandclark/index.html?loc=/lewisandclark/species.cfm?id=387

Collected by Meriwether Lewis near Kamiah, Idaho, on the banks of Clearwater River, probably at Camp Chopunnish, May 14, 1806.

First described by Frederick Traugott Pursh 1774-1820. The first botanist to publish on Lewis and Clark Specimens.

Linnaeus named the genus in 1773. Erigeron, Greek: Eri [early] + geron [old man, as in gerontology].

Southwest Colorado Wildflowers says they don’t know why ‘old man’ was appropriate.

Native Wildflowers of North Dakota Grasslands says ‘old man’ refers to early flowering plants with a hoary appearance.

Wikipedia thinks it’s the appearance of white hairs of fruit soon after blossoming.

Compositus means ‘compound’, probably referring to divided leaves.

The problem of burrowing around in miscellaneous photos taken over a long period of time trying to demonstrate botanical issues is compounded because there are three Erigeron in Drumheller Springs Park and there may be two more in the 1991 burn at Riverside State Park.

The problem is less with more recent photos because I photographed foliage as well as blossoms and because more recent photos are fairly well dated.

E. compositus blooms much earlier [April 17, 2012] than E. pumilus [June 26, 2012] and E. caespitosus [July 20, 2012]. [The date for E. compositus is for first blossom. The dates for E. pumilus and E. caespitosus are not. The plants were mature when I found them.]

I have no photos of ‘new’ E. compositus plants … seedlings. Something to watch for in 2013.

This is a mix of photos from six years of wildflower walks.

Six years ago I knew the common names of few wild flowers and the so-called ‘scientific names’ of none. [I’ll complain about the term ‘scientific names’ somewhere, sometime. Not now.]

And I didn’t know what botanists look for when they identify a plant.

Eventually I talked to a few botanists. Ken Swedberg explained that … for instance … there are a lot of pretty little yellow flowers. A photo of the face of the blossom is not enough to identify them.

I am calling this collection Erigeron compositus, tufted fleabane. But I am sure photos of other Erigeron species will intrude here and there.

It’s winter now. I expect to clean up photo errors next growing season.

Erigeron compositus occurs in all of the western states. It’s sparse in the southern tier states. It occurs in the western portions of North and South Dakota. It occurs in most Canadian provinces and in Alaska.

It likes it cool. It will be at high altitudes in the south and high latitudes in the north.

Burke’s distribution has it occurring in a rather strange pattern in Washington State, absent from counties of southwest, southeast, mid-state and from some Puget Sound counties.

Turner’s distribution map probably has the same source as Burke but includes Oregon. E. compositus occurs in most of Oregon but not in most Coast counties or most counties adjacent to the Columbia River.

Stem

E. compositus has a somewhat woody stem-base. It usually has more than one stem.

The stem and leaves have ‘spreading-hair’. I presume this means the ‘hair’ ‘sticks out’. That is the look of the hair in my photos. The term ‘spreading hair’ is mentioned in various sources.

Native Plants for the Intermountain West, of the University of Wyoming says “… leaves are hairy, protecting the plant from the blazing sun and constant wind of it’s native habitat. Very cold-hardy to zone 3 or 4.”

Leaves

Most leaves are basal. Its basal leaves are divided into threes, twice. Their leaf stalks are long and slender.

Turner has the basal leaves ‘spoon shaped’. I need to watch for a ‘spoon shape’ in these ‘deeply divided leaves’.

Cauline leaves [leaves on the stem] are linear. They are few and they are alternate.

All leaves are glandular. [My photos do not show glandular secretions. North American Flora says they are ‘minutely glandular’.]

Flowers

What seem to be flowers are flower-heads. They are a capitate inflorescence. ‘Capitate’, shaped like a head. Inflorescence, a collection of flowers. [The ‘head’ seems to be wearing a hat with a brim. Z]

Erigeron compositus is the first member of the Asteraceae family to bloom in the park in 2012.

Members of the Asteraceae family have an inflorescence made up of disk-flowers surrounded by ray-flowers. The ray flowers look like petals.

Some Asteraceae do not have both ray-flowers and disk-flowers. Taraxacum officinale, dandelions have only ray flowers. Senecio vulgaris, common groundsel have only disk flowers.

Erigeron compositus is sometimes ray-less but usually has both ray-flowers and disk-flowers. Turner says they are ray-less at higher altitudes.

From the Wikipedia article ‘Flower Symmetry’

Most flowers are actinomorphic, they are ‘star shaped’ or ‘radial’ … round. The overall shape cut in half may or may not have halves with mirror image.

Some flowers are zygomorphic, ‘yoke shaped’ or ‘bilateral’. Cut in half, the halves are mirror images.

There are a few other options but they are unimportant for now.

Zygomorphic flowers are thought to have been evolved from actinomorphic flowers.

Most Asteraceae inflorescences have both.

E. compositus has a round yellow disk of star shaped actinomorphic flowers surrounded by a ring of bilateral ray-flowers, the apparent petals of the ray-flowers in various colors.

The flower-heads have ray-flowers that are white, pink, or blue. But ray-flowers may be absent.

Erigeron compositus flower-heads are single, at the apex of stems. I don’t think E. compositus has branched stems. E. Caespitosus does have branched stems.

Burke says: “… pistillate flowers 20-60, with usually white but occasionally pink or blue rays …”. Apparently the ray flowers are all pistillate. I see nothing anywhere about staminate flowers. Are the disk flowers all staminate? Are the disk flowers mixed, pistillate and staminate? Non-sexual populations have no ray flowers. Do they not need pistils to reproduce?

The involucre [The ring of bracts at the base of the ray-flowers.]

The involucre, too, is glandular with ‘spreading-hair’.

The bracts are purplish, at least near their tips.

The bracts of the involucre are in one row.

Now yet another term for modified leaves: phyllaries … the bracts of an involucre. [Merriam-Webster Dictionary on-line: New Latin phyllarium, from Greek phyllarion, diminutive of phyllon leaf. First Known Use: 1857] ]]

Flora of North America says, “ … phyllaries in 2-3 series (purple-tipped), hirsute (hairs spreading), minutely glandular.”

I suppose that means that the ‘bracts’ of the involucre are in two to three rows. It may mean something else. I see that the glandular feature of the hairs is ‘minute’.

I’ll have to try to count rows of bracts in the involucre next year.

The fruit

It is a ‘2-ribbed’ achene [Achenes are indehiscent. They don’t break open.] ‘nutlet’.

Question: How do achenes open to expose their seeds?

It has short hair.

It has a pappus of 12-20 white, hair-like bristles. [Burke says: 12-20 ‘capillary’ bristles. So, 12 to 20 bristles on its head.]

I don’t have photos of a seed with a pappus.

This from The Dictionary of Botany: Pappus

A modified calyx made up of a ring of fine hairs, scales, or teeth that persist after fertilization and aid the wind dispersal of the fruit, often by forming a parachute-like structure. It is seen in members of the Compositae, e.g. dandelions (Taraxacum) and thistles (Carduus). The pappuses of an inflorescence may form a 'clock'

The gardeners are told not to cover E. compositus seeds, they need light to germinate. They do not need additional nutrients, even water. Just spread them on the ground.

Dave’s Garden says they may be short lived.

TC Gardens says they can be expected to live approximately ten years.

The American Journal of Botany, 1996 says E. compositus ‘… comprises both sexual and agamospermous populations.”

[Agomospermy: Any form of reproduction that involves the sex cell but takes place without fertilization or meiosis … parthenogenesis, apogamy and apospory.]

[Encyclopedia Britannica: Apogamy is believed to foster quick reproduction in connection with a brief damp period.]

It seems that agamospermous populations of E. compositus are characterized by ray-flowers absent or of reduced size. I don’t think all E. compositus with absent ray-flowers are agamospermous.

Apparently E. compositus of high altitudes and perhaps high latitudes are often agamospermous.

Native Wildflowers of North Dakota Grasslands says E. compositus are thought to drive away fleas, relieve toothache and cure various diseases.

The Photographs

I think this is the first Erigeron compositus I saw with buds in 2012

010-030

I don’t have photos of ‘new plants’. This specimen was taken from plant in the previous photo.

Notice the trifid [divided in threes] basal leaves on long stalks and the linear cauline leaves [stem leaves].

Some of these leaves seem to be twice trifid and perhaps three times trifid.

The bracts of the involucre have ‘spread hair’ and they have purple tips. It is not clear from this photo whether they have ‘one row’ or ‘two or three series’ of bracts. The photo suggests more than one ‘row’ to me.

Another look at linear cauline leaves.

The buds opening

The back of a bud

Ray flowers spreading, disk flowers maturing. Notice the petal-like stars on the disk flowers. I don’t know if we are looking at anthers or stigma or both.

Perhaps the small bright yellow dots at the base of rays are stigma and the large bright yellow ‘rods’ at anthers.

If that’s so then [perhaps] all ray flowers are pistillate and all disk flowers are staminate?

All Asteraceae disk flowers seem to mature from the outside to the center.

This view of the involucre is more clearly ‘three series’ of bracts. It wears a fur coat. Not every view of an involucre or bud is as ‘furry’ as this one.

Perhaps Erigeron compositus with redish ray petals. I may have ‘brought up the color’ in appropriately’. The greens, too, are quite dark.

Some blossoms. Apparently two colors of ray flowers on the same plant.

Notice the rather blunt ray flowers

More close ups of maturing disk flowers. Perhaps the pistils of the ray flowers are a little better displayed.

Some Erigeron blossoms with finer ray flowers. These are probably not E. compositus. The foliage is hard to see but it seems to be ‘broad leaf’ as in Erigeron caespitosus. The ray flowers are a little blue.

The involucre in 380 seems somewhat ‘shallower’ than Erigeron compositus.