Panicled Aster (Aster paniculatus)
Also known as Tall White Aster. A spectacularly beautiful plant, growing to eight feet and covered with starry white flowers. These plants grew along a corrugated steel fence near a railroad track in Oakmont.
From Gray’s Manual of Botany: A. paniculatus Lain. Stem smoothish, 0.5-2. 5m. high, much branched; the branches and scattered heads (about 2 cm. broad) loosely paniculate; leaves elongate-oblong to narrowly lanceolate, pointed, somewhat serrate or entire; the cauline 0.5-1.5 dm. long, about 1 cm. wide; involucre 8 mm. long; its bracts narrowly linear, with attenuate green tips, or the outermost wholly green; rays white or purplish, G-8 mm. long. Wet meadows, thickets, etc., throughout. Aug. -Oct.
(Gray also notes that this aster is hard to distinguish from several other species. The chief identifying characteristic of these specimens was their spectacular height, at least seven feet. This identification is our best guess.)