Tuesday, November 17, 2009

Autumn's Grape Fern

Long winter shadows set in at 3:40 p.m. that day, shadows impending sunset only 8 hours after I woke up. I spent the whole day outside on Wednesday, planting more daffodil bulbs, spreading leaf mold and compost everywhere, trying to gain as much sunlight-derived Vitamin D as possible. But merely being outside isn’t enough. My thrice weekly visits to the woods, even trashed out woods, seem to be integral to my health and well being. So I zipped across the ever-sprawling town and the complex network of late afternoon traffic to woodlands that likely haven’t burned in 80 years and are now under siege by a burgeoning deer population.

But grape leaf ferns (genus Botrychium) are out right now, harbingers of late autumn so I set out to find one before the deer ate it. I was a hair late as some woodland creature already took a bite out of the persistent deep green blade.

Four species of Botrychium can be found in Missouri’s woodlands throughout the year. B. virginianum is a delicate spring fern, popping up in mid-May throughout the Ozarks. B. biternatum is restricted to the Southeast Missouri Lowlands, and can be found during the fall next to the most common of the grape ferns, pictured, Botrychium dissectum var. obliquum. The elegant and deeply dissected B. dissectum var. dissectum grows in the eastern Ozarks, though remains somewhat uncommon. But B. dissectum var. obliquum is pretty common in low woods, ravines, cherty uplands, and grows in unburned sites with deer problems (so that must mean it's all over the Ozarks, she grumbles).

The grape leaf ferns all have a similar shape, each one sending up a triangular leaf-like blade. All but B. virginianum remain visible for months, even through winter. This is the time of year that you also might find a fruiting branch attached to the triangular grape fern leaf. This fruiting branch contains tiny round Pacman-like sporangia all crowded on what would otherwise have been a leaf. Most are a bit smaller than BB's. These Pacmen sporangia break open and release spores that produce new fern plants elsewhere. Some Botrychium species produce two triangular fronds side by side. My colleague swears that he once observed one frond of var. dissectum growing immediately next to one frond of var. obliquum. But were they from the same root structure? He refused to dig them up to find out.