CATALOGUE OF PLANTS. 147 This species and others, especially S. discolor, often bear cone-shaped galls on the ends of the branches. These consist of imbricated leaves, and are caused by the deposit of eggs of insects. 490 S. tristis, Ait. DWARF GRAY WILLOW. Rare. Hollows, between Northeast Harbor and Little Harbor (Rand). Perhaps introduced in this locality from beyond our limits. 491 S. petiolaris, Smith. Frequent. Somesville; Bass Harbor Marsh; Great Cranberry Isle; Long Pond meadows, etc. (Rand). The type passes into the next variety. 492 Var. angustifolia, Anders. S. rosmarinifolia (Herb. Hook.), Barratt & Hooker. Leaves narrowly lanceolate, almost linear, margin slightly serrulate or subentire, glaucous beneath, at first silky, at length glabrate. DC. Prod., xvi. 2. 234. Common on meadows and heaths. Long Pond meadows; Pond Heath; Northeast Meadow, etc. (R. & R.). The silky hairs of the young leaves are usually of a rusty color. 493 S. cordata, Muhl. HEART-LEAVED WILLOW. Rare. Roadside near Denning Pond; Southwest Harbor (Rand). 494 S. balsamifera (Hook.), Barratt. BALSAM WILLOW. Widely distributed, but nowhere very abundant. Southwest Harbor; Sargent Mt.; Beech Hill; Ripples Pond; Somes Pond; Denning Brook; Beech Mt. Notch; The Hio; Doctors Brook; road, west side of Browns Mt., etc. (Rand);—Seal Harbor (Redfield);—Browns Mt. (E. Faxon);—High Head meadow (Faxon & Rand);—Long Pond meadows (R. & R.). POPULUS, L. POPLAR. ASPEN. 495 P. tremuloides, Mx. ASPEN. Frequent in woods.