Fig. 156. Gum Arabic Tree (Acacia Senegal, Pulse Family, Leguminosoe). A, flowering branch. B, flower. C, pod, half, showing seeds. D, seed, cut between the seed leaves to show seed stem and seed bud. E, seed, cut across. (Taubert.) A tree about 6 m. tall; bark gray; leaves grayish; flowers yellow; pod yellowish. Native home, tropical Africa. This tree yields the best gum; several other species produce an inferior quality.

Fig. 156.-Gum Arabic Tree (Acacia Senegal, Pulse Family, Leguminosoe). A, flowering branch. B, flower. C, pod, half, showing seeds. D, seed, cut between the seed-leaves to show seed-stem and seed-bud. E, seed, cut across. (Taubert.)-A tree about 6 m. tall; bark gray; leaves grayish; flowers yellow; pod yellowish. Native home, tropical Africa. This tree yields the best gum; several other species produce an inferior quality.

Fig. 157. Tragacanth Shrub (Astragalus gummifer, Pulse Family, Leguminosoe). A, flowering branch. B, leaf from which the leaflets have disappeared, leaving only the stiff thorn like

Fig. 157.-Tragacanth Shrub (Astragalus gummifer, Pulse Family, Leguminosoe). A, flowering branch. B, leaf from which the leaflets have disappeared, leaving only the stiff thorn-like "rachis" and the toothed "stipules." C, flower. (Taubert.)-A shrub 30-60 cm. tall; flowers yellow; pod, small, one-seeded. Native home, Southwestern Asia.

Fig. 158. Marshmallow (Althcea officinalis, Mallow Family, Malvaceoe). Flowering top. (Baillon.) A perennial herb about 1 m. tall, downy throughout; leaves pale purplish; fruit dry. Native home, Eastern Europe.

Fig. 158.-Marshmallow (Althcea officinalis, Mallow Family, Malvaceoe). Flowering top. (Baillon.)-A perennial herb about 1 m. tall, downy throughout; leaves pale purplish; fruit dry. Native home, Eastern Europe.

Fig. 159. English Elm (Ulmus campestris, Elm Family, Ulmaceoe). 1, flowering twig. 2, leafy shoot. 3, flower, entire. same, cut vertically. 5, fruit. (Wossidlo.) Tree attaining 30 m.; leaves becoming smooth; flowers greenish or brownish; fruit yellowish. Native home, Eurasia and Northern Africa.

Fig. 159.-English Elm (Ulmus campestris, Elm Family, Ulmaceoe). 1, flowering twig. 2, leafy shoot. 3, flower, entire. same, cut vertically. 5, fruit. (Wossidlo.)-Tree attaining 30 m.; leaves becoming smooth; flowers greenish or brownish; fruit yellowish. Native home, Eurasia and Northern Africa.

Fig. 160. Sassafras (Sassafras officinale, Laurel Family, Lauraceoe). A, flowering twig of staminate plant. B, branch bearing leaves and fruit. C, staminate flower. D, pistillate flower. E, stamen, showing nectar glands at base of filament, and anther opening by up turned valves. E, pistil, cut vertically. (Berg and Schmidt.) Tree growing 20 30 m. tall; young branches green; leaves becoming smooth, aromatic; flowers yellow; fruit blue on red stalks. Native home, Eastern North America.

Fig. 160.-Sassafras (Sassafras officinale, Laurel Family, Lauraceoe). A, flowering twig of staminate plant. B, branch bearing leaves and fruit. C, staminate flower. D, pistillate flower. E, stamen, showing nectar glands at base of filament, and anther opening by up-turned valves. E, pistil, cut vertically. (Berg and Schmidt.)-Tree growing 20-30 m. tall; young branches green; leaves becoming smooth, aromatic; flowers yellow; fruit blue on red stalks. Native home, Eastern North America.

Fig. 161. Iceland Moss (Cetraria islandica, Shield lichen Family, Parmeliacece). Plant, natural size, growing nearly erect from dry earth. (Luerssen.) Upper surface brownish or olive, pale below, often red stained at the base; fruit forming chestnut colored patches on the uppermost lobes. Native home, North America and Eurasia.

Fig. 161.-Iceland Moss (Cetraria islandica, Shield-lichen Family, Parmeliacece). Plant, natural size, growing nearly erect from dry earth. (Luerssen.)-Upper surface brownish or olive, pale below, often red-stained at the base; "fruit" forming chestnut-colored patches on the uppermost lobes. Native home, North America and Eurasia.

Fig. 162. Licorice (Glycyrrhiza glabra, Pulse Family, Leguminosoe). Branch in leaf, flower, and fruit. (Baillon.) Perennial herb growing about 1 m. or more in height; leaves pale green; flowers violet or purple resembling those of a pea; fruit smooth. Native home, Mediterranean Region.

Fig. 162. - Licorice (Glycyrrhiza glabra, Pulse Family, Leguminosoe). Branch in leaf, flower, and fruit. (Baillon.)- Perennial herb growing about 1 m. or more in height; leaves pale green; flowers violet or purple resembling those of a pea; fruit smooth. Native home, Mediterranean Region.

Fig. 163. Medicinal Rhubarb (Rheum officinale, Buckwheat Family, Polygonaceoe). Plant in flower. A, flower, entire, enlarged. B, same, cut vertically. C, pistil; d, nectar glands. (Baillon.) Perennial herb growing 2 m. tall; leaves hairy; flowers greenish; fruit, dry, reddish. Native home, Central Asia.

Fig. 163.-Medicinal Rhubarb (Rheum officinale, Buckwheat Family, Polygonaceoe). Plant in flower. A, flower, entire, enlarged. B, same, cut vertically. C, pistil; d, nectar glands. (Baillon.)-Perennial herb growing 2 m. tall; leaves hairy; flowers greenish; fruit, dry, reddish. Native home, Central Asia.