May Phenology 1: First Flowering Dates

by Carl Strang

The end of May brings the next opportunity to compare seasonal timings between 2013 and the previous years. There’s nothing special in this choice, except that months are a familiar common language and they provide a sensible number of comparisons each year. The data I collect are limited to Mayslake Forest Preserve, because I am out in that property most regularly and so can make the most consistent comparisons. Today I’ll share the first flower dates, which provide the soundest results.

As expected, flowering phenology this May was much later than last year, a median 24 days later for 73 species. This is 10 days less than the April difference, but it is typical for the first flower dates to converge as the season progresses.

The broad-leaved woolly sedge, Carex pellita, was the median species this time.

The broad-leaved woolly sedge, Carex pellita, was the median species this time.

If we jump to the other early year, 2010, the difference also is less. The median first flower date was 12 day later in 2013 than in 2010 (54 species). The corresponding difference in April was 17 days.

Yellow sweet clover fell on the 12-day median difference.

Yellow sweet clover fell on the 12-day median difference.

The surprise came from the comparison between 2013 and the other late years, 2011 and 2009. The median difference was exactly 0 days for 2011 (67 species), and 2013 was only one day later than 2009 (53 species; the respective differences were 4.5 and 5 days in April).

Common spiderwort first bloomed one day later in 2013 than it did in 2009.

Common spiderwort first bloomed one day later in 2013 than it did in 2009.

All of this continues to underline how unusual last year was.

West Bluffs Walk: 2

by Carl Strang

Yesterday I shared the tracking highlights of my recent walk through south Waterfall Glen Forest Preserve. Today, some winter botany. These are not unusual plants, but such a large area provides a lot of good examples to choose from for photos. The first species is one I haven’t found at Mayslake Forest Preserve, my main area for botanical study.

Someone familiar with this species will recognize it from this photo.

A closer view of the distinctive fruiting stalk reveals it to be lopseed.

Another woodland herbaceous plant, and one of our most common, is the wood avens, also known as white avens.

Again, if you are familiar with this one, this photo is enough.

Close up, the seeds in their loose ball project the hook-like extensions that latch onto fur or clothing for dispersal.

In this case I have a flower photo to show.

Wood avens is in the rose family.

One more common woodland plant, this time beginning with the seed array:

Again, little hooks serve to aid dispersal.

Here is the entire plant, a woodland knotweed.

I’ll close with a weedy plant from the Old World. It grows in the open, and belongs to one of two species. I do not know how to tell them apart without the flowers.

The sprawling, spindly plant form is rather nondescript in winter.

The seeds, many of which have been knocked off at this point in the season, have a vanilla flavor if chewed. I don’t recommend chewing on unfamiliar plants, however.

When blooming it looked either like this:

White sweet clover

Or this:

Yellow sweet clover

All in all, this was a satisfactory walk even without the spice of bobcat tracks.

More Weeds

by Carl Strang

Time to catch up on the weeds at Mayslake, as many more have begun to bloom. Remember that here I am using a very broad definition for “weed,” that includes the meanings of undesirable plant, plant not native to the area, and plant with a weedy life history strategy . An example of a native plant in the last category is annual bedstraw.

Annual bedstraw b

The rest of today’s species are imports. Two are from Asia, and perhaps it is no coincidence that these two both had specific agricultural uses. One is alfalfa.

Alfalfa b

The only place I have seen alfalfa at Mayslake so far is in a location that once held a dairy farm, and I wonder if this plant’s history traces to that operation. The other Asian weed also very much meets the definition of “undesirable plant.”

Multiflora rose b

Multiflora rose was widely planted as a thorny hedge, decades ago. Too late people realized how uncontainable this shrub is, and I have gotten many a piercing while trying to remove it from places under my protection. The rest of today’s weed list comes from Europe, and most probably were hitchhikers. One exception is red clover.

Red clover b

Another, European highbush cranberry, is planted widely as a landscape shrub.

European highbush cranberry 2b

Crown vetch has been planted in an effort to control erosion and enrich the soil cheaply in highway construction projects.

Crown vetch 1b

Like multiflora rose, it has become a problem plant because it won’t stay put. As far as I know, the remaining European species were incidental rather than intentional imports. These include ox-eye daisy,

Ox-eye daisy b

sulfur cinquefoil,

Sulfur cinquefoil b

bittersweet nightshade,

Bittersweet nightshade b

English plantain,

English plantain b

and yellow sweet clover.

Yellow sweet clover b

So far I have not seen white sweet clover at Mayslake.

%d bloggers like this: