I didn’t let summer’s final gasp of heat and humidity deter me from a walk in the Arboretum on Wednesday, although, after a month-long break in 90-degree heat, I felt like I was experiencing the first hot day of the season. I spotted a nursery web spider (Pisaurina mira) biding its time under a leaf. Note how it rests with its two front legs touching each other.
This spider has a dark stripe running down the middle that is bordered by a white margin, which undulates along its abdomen. Also note the white hairs along its body and the black spines on its legs.
I passed a European alder tree (Alnus glutinosa) on Willow Path at the Arnold Arboretum a couple days ago (accession 1399-73*B), and noticed that many of its branches were covered in a white fungus/mold-like substance. Upon closer inspection, the mold moved!
On Tuesday, I walked from the Arboretum’s main gate to the shrub garden. I saw a couple of butterflies for the first time, among them a common sootywing (Pholisora catullus), a dark brown butterfly with white spots.
Late last week, I went to the Explorers’ Garden on Bussey Hill on a pleasant, sunny day. A few butterflies passed me by but did not perch. The eastern kingbird below paused at a the top of a crabapple tree. In about a month, this kingbird will probably make its way to South America for the winter.
I found this white-dotted prominent caterpillar (Nadata gibbosa) crawling across Meadow Road yesterday. A green caterpillar with an opaque, lighter green face, it is covered with white dots. This one had two brown patches on it, perhaps some sort of infection?
Exploring in the meadow of the Arnold Arboretum last weekend, I came upon this giant water bug (Belostoma sp.). This large insect — they named it “giant” for a reason — preys on creatures as large as small fish. It can inflict a very painful bite, and so is also called toe biter. Thanks to John Epler for the ID.
I like to call Ailanthus altissima the tree of good or evil. Depending on your perspective, it is either the “ghetto palm,” an invasive pest, or the “tree of heaven,” a tough, hardy street tree once planted for its beauty.
Introduced into the United States from China in 1748, it was being planted as a street tree by the 1820s. Pollution-resistant, salt-tolerant, quick-growing, and with tropical-like foliage, what was not to love about this tree?
Peter Del Tredici, senior research scientist at the Arnold Arboretum, held a tree mob on July 22 on a specimen of this tree (accession #695-80-B). Before eventually turning brown, most ailanthus trees have fruit that go from green to yellow. The tree that Del Tredici collected goes from green to red, hence the form “erythrocarpa,” which means red fruit. Del Tredici described the red on the tree as a spontaneous mutaton that appears sporadically. Continue reading →
Can Southern magnolia trees survive in Boston? I thought not. Even the Arboretum’s own Bulletin of Popular Information, didn’t think so, saying in May of 1911 that Magnolia grandiflora is “not hardy at the north.” That changed in 1983, when a tree was planted behind the Visitor Center. More accessible, however, is a tree just off Meadow Road behind a red maple. Planted in 1998, this cultivar — Bracken’s Brown Beauty — is doing very well.