Arquivos de periódicos de março 2015

29 de março de 2015

White Clay Creek walk, March 28

I've been out scouting recently in preparation for doing some wildflower hikes in the White Clay Creek parks. I don't have pictures from my March 21 hike (I'll probably go back and get some), but I was fortunate enough to find all three of what I think of as our "winter orchids": orchids that stay in leaf all winter. One of these is Goodyera pubescens, downy rattlesnake-plantain, which holds its leaves year-round. A relatively common one, although I don't see it that frequently in the Delaware Piedmont. The other two carry their leaves through winter to capture the sunlight no longer blocked by the canopy, but lose their leaves before flowering in summer. The more common of the two is Tipularia discolor, the cranefly orchid, which usually shows a striking magenta-purple beneath (although I have seen what appears to be f. viridifolia, which is largely green beneath, with traces of purple on the venation). These often show raised purple dots on the upper surface. The third, to my happy surprise, was Aplectrum hyemale, puttyroot, a rare species in Delaware. It has a distinctive "pinstriped" appearance, with thin parallel white veins running the length of the leaf. A little scouting revealed a very large quantity of puttyroot spread over the site. The whole hike more or less lies within a tulip-tree forest with an unimpressive shrub layer (mostly Rosa multiflora); most of it was wooded in 1937, but I think this site would have been very close to the wood edge. It isn't what I'd think of as rich, high-quality woods, but I found a large colony of Aplectrum in similar habitat elsewhere in the park a few years ago. Also a few leaves of Anemone americana, hepatica, but the puttyroot really took the prize.

My walk on the 28th, which is documented, was up on the Pennsylvania side (White Clay Creek Preserve). A trail on the east side of the creek climbs the edge of a steep, northwest-facing slope covered in an oak-heath forest. (The oak-heath forests I see have a heavy admixture of beech; I assume this is due to some combination of reduced fire and deer browse on oak seedlings.) While strolling along in one direction, I noticed some Epigaea repens sprouting at trailside; another happy find, as I don't see that very often along the Pennsylvania-Delaware border. When I came back to take a picture, it took me about four tries to find it again, even with GPS coordinates...elusive!

My friend Janet Ebert has had me looking for clubmoss in this part of the Piedmont lately (not that it takes much); she feels the Delaware Piedmont is losing most of its clubmosses as earthworms invade the forests and break down leaf litter, so I've been on the lookout for Dendrolycopodium and the like. I found several little sprigs of shining clubmoss, Huperzia lucidula, growing along the trail in one area. Huperzia s.s. produces gemmae which allow it to disperse vegetatively, and to my excitement, the sprig that I photographed appears to be growing from a gemma. Naturally, I looked upslope for a possible source, but without success; the slope is steep and bare, and a parent colony would have been obvious. There's a very large colony of H. lucidula about a third of a mile downstream; maybe the source is closer, but regardless, it seems like the gemmae have more dispersal potential than I would have assumed. I took pictures of some of the common oak-heath-beech understory flora.

Elsewhere in the preserve, I did stumble upon a patch of Dendrolycopodium obscurum, as yet unfazed by worms. I'm surprised I hadn't noticed it before, or maybe I just forgot. I also took a picture of Polystichum acrostichoides, the very common Christmas fern, helping hold down a slope nearby. They're very common on steep, eroding slopes, perhaps because they provide good habitat for gametophytes.

Posted on 29 de março de 2015, 04:16 AM by choess choess | 8 observações | 0 comentários | Deixar um comentário