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Welcome to bobklips.com, the website of Bob Klips, a plant enthusiast living in Columbus, Ohio.

Silver Maple
Marion Cemetery, Marion, Ohio
March 17, 2009

The first tree flower of spring, silver maple (Acer saccharinum, family Aceraceae) is an abundant species of moist or wet soil. It is commonly planted along roads, and in parks and cemeteries such as the Marion Cemetery in Marion, Ohio. Silver maple flowers are inconspicuous, but often get noticed as an early sign of spring, albeit slightly misinterpreted as people cheerfully report seeing maple "buds."  Actually, silver maple buds are evident throughout the winter, and the striking change we see in early-mid March is the actual emergence of flowers from the buds  

Over the winter, silver maple flowers were contained within globose clusters of lateral buds. Here's what their twigs looked like during midwinter, 2008.

silver maple twig
Silver maple winter twig showing clusters of flower buds.

Like many tree flowers, silver maple sexual expression isn't very clear-cut. At the Marion Cemetery, some individual trees seem to have only flowers all of one sex, either male ot female but not both. Yet some had both male and female flowers, located on different parts of the tree. And some seemingly pistillate (female) flowers appeared to have stamens, but they were tucked deep in the blossom, unexpanded.

For interpretive guidance, it helps to consult a
detailed and authoratative botanical manual. Here's what H.A. Gleason said about maples in the best book ever written, New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada:

maple description in Britton and Brown
Description of maples from a regional flora, H.A. Gleason's New Britton and Brown (1952).

That helps. We're looking for unisexual flowers, but they might only be "functionally" unisexual, i.e. possessing vestigial organs of the unexpressed sex. Further, Gleason tells us that silver maple flowers lack petals, and, moreover, that each flower cluster is either wholly staminate or wholly pistillate. Although the manual doesn't say so, it seems like some trees are wholly staminate, some are wholly pistillate, and still others are a mixture (monoecious). The following pictures are from separate trees, both of which appear to be unisexual.

Here are male flowers. Note the slender filaments sticking pollen-containing anthers well out into the breeze. (The species is wind-pollinated.)

silver maple male flowers
Silver maple male flowers. March 17, 2009. Marion, Ohio.

...And here are the female ones. Note the two elongate style-branches, well positioned to receive wind-borne pollen.

silver maple female flowers
Silver maple male flowers. March 17, 2009. Marion, Ohio.

While scouting the vicinity west of Marion near the Little Sandusky River for suitably photogenic silver maples, it was a thrill to see a bald eagle flying overhead, attracting also the attention of a red-tailed hawk.

bald eagle and red-tailed hawk
Immature bald eagle being harassed by red-tail. West edge of Marion, Ohio. March 17, 2009.

Skunk cabbage.
Delaware County, Ohio.
March 8-13, 2009.
The first wildflower of spring, skunk cabbage (Symplocarpus foetidus, family Araceae) is a rugged and long-lived perennial that can be extremely abundant in open bottomlands such as this area along a tributary to Alum Creek in eastern Delaware County, Ohio.

skunk cabbage site
Skunk cabbage growing in open area along woodland creek. March 8, 2009, Delaware County, Ohio.

Skunk cabbage is famous for its ability to generate heat and plants can sometimes be seen iconically poking their noses through a late-winter blanket of snow, as seen last year at this same location.

skunk cabbage poking through snow
Skunk cabbage poking through snow, March 1, 2008, Delaware County, Ohio.

Skunk cabbage leaves appear soon after the flowers. Here's what they looked like in mid-April a few years ago.

skink cabbage
Skunk cabbage. April 15, 2006. Delaware County, Ohio.

The arum family is distinguished by a unique type of inflorescence consisting of a dense flower spike, the spadix, situated beneath a large overarching bract, the spathe. A familiar example is the woodland wildflower Jack-in-the-pulpit (Arisaemia triphyllum) wherein the spadix is the preacher "Jack" and the spathe is his pulpit. Another arum species, green dragon (A. dracontium), looks like a dragon, I guess. Here's what these two woodland wildflowers looked when they were blooming in mid-May within the past few years.

jack-in-the-pulpitgreen dragon
Representative members of the arum family (Araceae).
Left: Jack-in-the-pulpit. Hocking County, Ohio, May 9, 2005.
Right: green dragon.
Delaware County, Ohio, May 19, 2008. 

The skunk cabbages are in full bloom this week. Here's a typical pair of inflorescences, wherein only the spathes are visible, as each spadix is nearly completely concealed within its spathe. To more fully understand these inriguing (and very abundant) flowers, I sectioned a spathe to expose the spadix within.

MOUSEOVER the IMAGE to see the spadix. skunk cabbage
Skunk cabbage inflorescences. March 8, 2009. Delaware County, Ohio.

The head-like spadix consists of many small flowers tightly packed together. Gently prying apart the margins of the spathes of several plants and peeking within, it is evident that all of a spike's flowers develop simultaneously. Moreover, there are three evident stages of development, presented below.

(1) A stage when the only visible sexual parts are the female stigmas (i.e., no stamens).

skunk cabbage pistillate
Skunk cabbage inflorescence, pistillate (female) stage. March 9, 2009. Delware County, OH.

(2) An almost pathologically gooey stage marked by prominent and wierdly soaked-appearing stamens.

skunk cabbage staminate
Skunk cabbage inflorescence staminate (male) phase. March 13, 2009, Delaware County, Ohio.

(3) A stage with obviously "spent" (dehisced) anthers and copious amounts of dry dusty pollen at the base of the chamber.

skunk cabbage late stage flower
Skunk cabbage late-stage inflorescence. March 11, 2009. Delaware County, Ohio.

Swayed by the striking differences between these presentations I jumped to an initial cursory but wholly incorrect supposition that the species is dioecious (separate male and individuals). 
Interpretation of the structure of small and somewhat modified flowers can be challenging, and is best done by methodically checking observations of flowers made through a lens against their description in a detailed and authorative botanical manual. Here's what H.A. Gleason said about skunk cabbage in the best book ever written, New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada:

skunk cabbage description
Description of skunk cabbage from a regional flora, H.A. Gleason's New Britton and Brown (1952).

Surprise! These plants are not dioecious or even monoecious; the flowers are "perfect" (hermaphroditic, bearing both stamens and pistils). It is evident therefore that skunk cabbage exhibits "protogyny," a sequential maturation of the differently sexed flower parts, wherein the female pistil ripens first.

The following is a studio portrait of a portion of a spadix during the early, female, stage of flowering. Using a sharp razor blade, a thin tangential slice was made through through the spadix, resulting in an upper  cross-section of several flowers, exposing and making evident some of the floral features spelled out in the Gleason synopsis. Progressing inwards these are:  the 4 perianth segments, the anther portions of the 4 stamens, and the central angular style portion of the pistil. In the unsectioned face view, the upper portions of the perianth segments and the stigma portion of the pistil are visible, but the stamens are not.

MOUSEOVER the IMAGE to see the flower parts labelled. skunk cabbage pistillate spike
Skunk cabbage spike in early (pistillate) stage showing 4 perianth segments,
4 anthers (sectional view only), the stout central style (sectional view only) and stigma (intact face view). 

When it's time to disperse pollen, the filaments elongate and push the anthers out from their comfortable nest between the perianth segments and the pistil. Afterwards, the anthers are evident, clearly exert above the perianth. A tangential sectional similar to the one above reveals filaments positioned where previously there were anthers.

MOUSEOVER the IMAGE to see the flower parts labelled. skunk cabbage pistillate spike
Skunk cabbage spike in late (staminate) stage showing 4 perianth segments (shaded),
anthers (showing in intact face view only), filaments (in section view only), and the stout central style.
What loggers call a "radial section," i.e., a longitudinal cut that passes through the center of a cylinder, of the spadix reveals longisection side views of individual flowers. This view shows what Gleason was referring to with "Ovary buried in the tissue of the spadix, 1-celled, 1-ovuled; style stout, elongate." It would be nice to return in a month or so and see the "Seeds embedded in the large spongy spadix, covered by the persistent perianth and style."  

MOUSEOVER the IMAGE to see the flower parts labelled. skunk cabbage ovary view
Radial section view of skunk cabbage spadix,
showing individual flowers in longitudinal view.
Note ovary buried in spongy tissues of the spadix.

This has all been pretty technical. So as not to lose sight of the elegant beauty of these exceptional wildflowers, here are a couple of skunk cabbage snapshots, unmolested by the botanist's scalpel.

skunk cabbage backlit
Skunk cabbage. March 8, 2009. Delaware County. Ohio.

skunk cabbage group
Skunk cabbage. March 8, 2009. Delaware County, Ohio.

Drippy Tree!
Roadside sugar maple gives car a sweet shower.
March 8, 2009

This time of the year, maple sap is flowing freely, and the local syrup producers are hard at work, as this excellent article in the Columbus (Ohio) Dispatch attests. 

sugar maple article

The Clintonville neighborhood of Columbus is enhanced by the presence of a great variety of roadside trees. Some of them are forest giants that annoy the electric, phone and cable companies and also stand scarily  sword-of-Damacles-like over some of the houses. One such tree is a majestic sugar maple that seems to be declining a bit and so has some broken branches, probably a result of the September 2008 windstorm that spun off of Hurricane Ike.

google earth maple view
Google Earth aerial view of roadside sugar maple (2004).

Parked beneath this maple is a red 1994 Honda Civic del Sol that looks all drippy, as if it was rained on, but it hasn't rained lately! A taste-test revealed the drops to be faintly sweet. The overarching sugar maple, emulating its syrup-serving country brethren, has its sap flowing too, and it leaked, sugar-coating the car!

car covered in maple sap
Sap-soaked top of red car parked beneath roadside sugar maple. March 8, 2009.

Earlier observations ("next")