Sweet Alyssum

Lobularia, a non-native plant, is easily identified by its white flowers and long slender leaves. It is common throughout the island. The cotyledons are ovate and can be difficult to differentiate from other plants, especially Verbesina.  The first two true leaves also briefly resemble Verbesina leaves before they grow into the long slender form characteristic of adult plants.

Lobularia cotyledons are ovate to egg-shaped and can be differentiated from Verbesina by the shape of the base of the leaf, which rounds sharply to the stem. When very young, before the leaves are well separated, it can be somewhat difficult to see this part of the leaf.

As the seedling grows the stem elongates and the first two true leaves appear. When very small these also resemble Verbesina leaves, but as they grow they soon become much longer and slender than Verbesina. Lobularia stems range in color from white to light purple.

Though not truly glabrous, the hairs that eventually cover the surface of Lobularia leaves are very fine and are appressed (lying flat). The first true leaves (below left) generally appear hairless and hence shiny.  At later ages, the hairs give the leaves a soft white-green or silvery appearance.

Description: Herbs perennial, sometimes suffruticose, (5-) 12-24 (-40) cm tall, silvery pubescent. Stems erect, ascending, procumbent, or decumbent, basally branched; pubescent. Leaves linear, lanceolate, or oblanceolate, (1-) 1.5-2.5 (-4) cm x (0.8-) 1.5-3 (-6.5) mm, pubescent, base attenuate, margin entire, apex acute to subobtuse. Racemes many-flowered elongated considerably in fruit. Fruiting pedicels divaricate or ascending, straight, slender, (3-) 5-7 (-10) mm, pubescent. Sepals green or purple, oblong, 1.5-1.8 (-2.4) x 0.5-1 mm, pubescent. Petals white or deep purple, obovate or

suborbicular, 2-3 x 1.5-2.5 (-3) mm, abruptly narrowed to claw; claw to 1 mm. Filaments white or purple, 1.2-2 mm; anthers ovate, 0.3-0.5 mm. Fruit ovate, elliptic, or orbicular, (2-) 2.3-3 (-4.2) x (1.2-) 1.5-2 (-3) mm; valves convex, pubescent, with a distinct midvein; style 0.4-0.6 mm. Seeds light to reddish-brown, 1 per ovary, lenticular, ovate or suborbicular, wingless or with a narrow wing to 0.1 mm wide (Flora of China online).