Water Lily Pollination

Many Fragrant Water Lilies (Nymphaea odorata) bloom in our lake in July and August. The flowers are showy yet I had not noticed insects attracted to them, which caused me to wonder about its strategy for pollination. Investigation revealed that these plants have a very interesting reproduction process.

Hazy sunrise with Water Lilies

Each flower of the Fragrant Water Lily has a three-day life span, they close each night and open during the day.

The first day of a bloom’s life only its female portion, the stigma, is mature. The bloom does not open completely, so the flower has the form of a closed bowl. A sweet-smelling viscous fluid is secreted by the plant and fills the bottom of this bowl. Beetles, flies and other insects are attracted to this fluid. When they enter the flower, the slippery fluid causes them to fall and deposit on the stigma any pollen that they may have brought in from other flowers.

On the second and third days of a bloom’s life the pollen-producing anthers are mature and the flower opens wide to welcome pollen-spreading insects. Self-fertilization of the flower is prevented because pollen-production in each flower occurs only after the first-day fertilization of the stigma.

Water Lily flower in early morning
Water Lily bloom has opened in the afternoon

Once a fertilizer flower has completed its three-day cycle it closes and retracts under water to develop its seeds.

The short video below shows a Water Lily bloom bobbing with gentle waves in the lake. It seems reasonable that this bobbing action could help deposit pollen on the stigma (first day) and improve the chances that visiting insects will leave the flower carrying some of its pollen (days two and three).

Our Steadfast Bluegill

At our lake in north-central Minnesota we have often noticed circular areas on the lakebed, each a few feet across, where bottom muck is cleared away to reveal sand beneath. With a little research we discovered that bluegill sunfish were likely responsible, and that these circles are their nests. But we had not seen fish actually inhabiting these circles — up until this June.

In the first days of June we noticed a bluegill sunfish sticking very close to his circle-nest just a few feet to the right of our dock. Remarkably, nearly every day of June we found him in the same spot hovering in his nest and only occasionally darting out, typically to chase away other fish.

With a bit more research we learned that this is very typical behavior for a male “parental” bluegill. In fact, the reproductive strategies of male bluegills are very interesting and unusual. A comical description of bluegill behavior is given by a YouTube video titled “The Absurd Mating Strategies of the Bluegill Sunfish”.

The video tells how the male “parental” bluegills work hard building a nest to attract females, only to deal with competition from other male bluegills called “sneakers”. Rather than compete with the terrific job the video does in providing the intimate details, I’ll end this post with a few images and videos of “our” bluegill.

June 17, 2021

Wildflowers Flourishing in Dry Utah

The summer of 2021 has been exceptionally dry in Utah. Despite this several hardy wildflowers are flowering along hiking trails at high elevations east of Salt Lake City.

Think of the water that could be saved by replacement of grass lawns with attractive plants like these.

Sticky Geranium (Geranium viscosissimum)
Lewis Flax (Linum lewisii)
Parsnipflower Buckwheat (Eriogonum heracleoides)

Roses in a Cold Climate

Roses can be successfully grown in cold climates, like our area in Northern Minnesota which is in USDA hardiness zone 3 (very cold winters). Helpful web pages from the Minnesota Rose Society and Gardening Know How provide terrific information on proper selection and care of roses that can survive even brutal winters.

Alternatively, there are roses that grow wild in our area that thrive with very little care. The pictures below are of a wild rose bush moved from our woods to become part of our landscaping. It is most likely a Smooth Wild Rose (Rosa blanda), although it could be either of two very similar species, a Prairie Rose (Rosa arkansana) or a Wood’s Wild Rose (Rosa woodsii)

Oaks of Northern Minnesota

Seven species of oak trees are native to Minnesota, according to the website of the Minnesota DNR. Three of these are found in northern Minnesota; the Bur Oak (Quercus macrocarpa), Northern Red Oak (Quercus rubra), and Northern Pin Oak (Quercus ellipsoidalis).

There are two main groups of oak trees, the white oaks and the red oaks. Leaf shape is the easiest way to distinguish between these two groups of oaks. Leaves of white oaks typically have rounded lobes, while red oak leaves have several pointed tips. The Bur Oak is a white oak and the Northern Red Oak and Pin Oak are red oaks.

Leaves of the northern Minnesota red oaks, the Pin Oak and the more common Northern Red Oak, are shown in the picture gallery below. These trees are difficult to tell apart. Pin Oak leaves typically have deeper indentations between their pointed lobes. I believe the leaves in the two pictures in the upper row are from Pin Oaks while Northern Red Oak leaves are shown in the bottom row.

Leaves of the Bur Oak are shown in the following picture gallery. Bur Oak is the only white oak commonly found in northern Minnesota, the rounded lobes of its leaves are diagnostic of white oaks.

Oaks rely on the wind for pollination, which requires them to produce enormous amounts of pollen. Oak pollen is shed from male flowers called catkins over a period of about four days each spring. The picture below shows catkins hanging from a branch of a Bur Oak.

May 29, 2021

The images below compare a Bur Oak nearly leafless in mid-May and later in mid-June with its full complement of leaves.

Bur Oak, May 15 and June 12, 2021

Hawk’s Nest in our Sweetgum Tree

A pair of hawks have built their nest in the sweetgum tree in our front yard in Louisiana. The nest is too high for us to see any chicks, but there are calls that sound like chicks and the two adult hawks seem to be tending a brood.

Identification of the hawk’s species was difficult because we have only seen the birds fleetingly from a distance. Our first guess was the broad-winged hawk, but by comparing their calls to on-line references, I am now fairly confident that they are red-shouldered hawks.

Our hawk’s call is heard in this video

The call of this hawk compares closely to calls of the red-shouldered hawk that are available at this link.

Red-shouldered hawks are birds of the woodlands, found throughout the southeastern United States and also in California. In the south these hawks do not migrate far, and they commonly use their nests for more than one season.

Red-shouldered hawk near its nest in our sweetgum tree.

Historically red-shouldered hawks have been one of the most common hawks in North America, but deforestation has greatly reduced their numbers. They are now found occasionally in wooded suburban areas. They most commonly nest in tall deciduous trees, like our sweetgum.

One of the hawks flapping as it moved from one branch of the sweetgum to another.

Advocating for Planting Roses

Rose plants in your landscape reward a little effort with terrific value. Over the past month in my yard in SE Louisiana several roses have exploded with blooms. Some of these roses also bloomed in the winter months, but then it was just one flower at a time and the blooms developed over several weeks.

The pictures below feature two quite different kinds of roses from my yard this April. The red roses are “Knockout” roses, which are hardy, disease resistant, and repeat bloomers. All the other pictures show English roses that are fancier, but require a bit more tending.