ACANTHORHIZA (from akantha, a spine, and rhiza, a root). ORD. Palmae. A small genus of stove palms, differing from Trithrinax by the aerial roots of the trunk hardening into spines (which are horizontal or pointed upwards), and by the blade of the leaf being divided down to the petiole. They delight in a rich loamy soil, and are propagated by seeds, in a moist, sweet hotbed, in spring. ACANTHORHIZA aculeata (spiny).* l. orbicular, palmately slit into numerous linear-lanceolate, glabrous segments, deep-green above, silvery beneath; petioles slender; the trunk is covered with a network of branching spines. Mexico, 1879. SYN. Chamaerops stauracantha. ACANTHORHIZA Wallisii (Wallis's).* A recent introduction from tropical America, and not yet much cultivated; it is a tall palm with orbicular palmate leaves. ACANTHORHIZA Warzcewiczii (Warzcewicz's).* This differs from the preceding species by its more irregularly divided leaf blade, which is white below. Tropical America.