More Mayslake Fruits

by Carl Strang

Earlier I featured several plants at Mayslake Forest Preserve that produce fruits timed to coincide with the fall migration of berry-eating birds. This mutualistic interaction for the most part benefits the birds, through nutritional provisioning, while the plants get their seeds dispersed. Today I want to feature some outliers to this pattern. Let’s start with Solomon’s plume, also known as false Solomon’s seal.

Solomon's plume fruit b

Like many fall fruits, these advertise themselves to birds with a bright red color. When analyzed, however, the berries proved to be junk food, or perhaps are more accurately described as food mimics (White and Stiles 1985, Ecology 66:303-307). The plants save their energy, investing no nutritional value in these fruits. The ruse works, apparently, by exploiting the naïve instinctive response of first-time autumn migrants, the young of the year. A little different from this is the offering of the European highbush cranberry.

European highbush cranberry fruit b

Another study (Witmer 2001, Ecology 82:3120-3130) showed that the nutritional value of these berries becomes available only when they are consumed along with a significant protein source. I was impressed to learn that, like the waxwings native to the shrub’s European home, our North American cedar waxwings ignore these tempting berries until spring, when cottonwoods or other poplars are flowering. Then the birds consume the berries along with cottonwood catkins, protein in the pollen providing access to the berries’ nutritional value.

Common buckthorn fruit b

These black berries are common buckthorn fruits. They generally are ignored by birds until late winter when, apparently, the better quality foods have been depleted. Then, robins and waxwings consume them, unfortunately dispersing the seeds throughout our woodlands. Buckthorns leaf out early and lose their leaves late, casting a shade so dense that no other plants can grow beneath them. This is why these Eurasian shrubs must be removed at the beginning of woodland restoration projects. A final fruit is of no interest to birds.

Buckeye fruit 2b

Ohio buckeyes in fact are largely ignored by animals generally. This opens the possibility that, like other trees I discussed earlier, buckeyes may have been dispersed by now-extinct mastodons and other large herbivores.

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.

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