National Geographic : 1947 Jul
Australian Plants and Geography T HOSE of us whose business it is to study the natural distribution of plants are in trigued by those of Australia. Many plant groups of this continent have close con nections elsewhere, for example with those of Africa, and by way of Tasmania and New Zealand with those in southern South America. These relationships are so close that we are forced to the conclusion that at one time Australia was in some way connected by land with these areas now separated by thousands of miles of ocean. Later, Australia became isolated from the rest of the world-and for a period sufficiently long that on it were developed characteristic and often peculiar species of animals and plants. The last of the great inhabited land masses of the world to be discovered, Australia had many excellent items for gardens which now are widely grown. In 1768 Sir Joseph Banks and his associate Daniel Solander (southern gardeners remem ber him in the genus Solandra) sailed with Captain Cook on the first of his memorable voyages. From the region about a certain bay in Australia they collected a thousand different species of plants. With a nearly blank map before them the temptation was too much and so, to commemorate this great haul, the place was named Botany Bay. EUCALYPTUS or GUM-TREE (Eucalyptus, various species): The approximately 300 spe cies of Eucalyptus-one of which is shown in the distance in our picture-are mainly Aus tralian. Being trees primarily of warm areas, they have been widely planted in tropical and subtropical regions. Some are rapid growers and yield firewood and lumber in a com paratively few years. In parts of South America where the forests have been demol ished by thousands of years of human occu pation, Eucalyptus has been introduced and in various places is almost the only tree seen on the landscape for miles. Certain species, as the Blue Gum (E. globulus), are often grown in California and to some extent in Florida. In its home in Australia the Blue Gum may reach a height of 300 feet. Other species are naturally lower growing and often strikingly ornamental. Some have bright scarlet or pink flowers (e.g., E. fici folia), and others have curiously shaped, grayish-silvery leaves (e.g., E. polyanthemos). In all, about a dozen species are regularly cultivated in California, and many more are available from nurserymen. Because of the unusual shapes and colors of the leaves, espe cially on young shoots, branches of various species are now harvested commercially and often seen in florists' shops. The Eucalyptus belongs to the Myrtle Family. This large family of plants, with about 75 genera and 3,000 species, has many horti cultural members, of which the true Myrtle of the Classical Period-and native around the Mediterranean-is only one. Those who live in tropical or subtropical regions are likely to have growing in their gardens such interesting fruit-trees of the Myrtle Family as the South American Pitanga or Surinam-Cherry, the Malayan Rose-Apple, the Australian Brush Cherry, the East Indian Jambolan-Plum, and the tropical American Guava. Cloves are the flower buds of one member of this family native in the Moluccas, and Allspice is the dried, unripe berry of another found in the West Indies and Central America, whereas bay rum is distilled from the leaves of still another native in the Caribbean and northern South America. BOTTLE-BRUSH (Callistemon rigidus): This also is a member of the Myrtle Family. There are about 25 species of this showy Aus tralian genus of shrubby trees, some with wider and others with narrower leaves than the one shown at the top of our picture. The closely related and quite similar Australian Cajuput-Tree or Punk-Tree (Melaleuca Leu cadendra), with its dense clusters of creamy white flowers, is often planted in Florida, where it has escaped and in places become weedy. STRAWFLOWER (Helichrysum bractea tum): The Strawflowers are so common that we are inclined to forget that their native home is Australia. Cut at the proper stage as they open and hung upside-down to dry, they make excellent "everlasting" winter bou quets. The name Helichrysum was most aptly compounded from two words meaning "sun gold." SWAN RIVER DAISY (Brachycome iberidi folia): Named for its native region in Austra lia, this pretty and easily grown annual is worthy of a place in any garden. BLUE LACE-FLOWER (Trachymene caeru lea): Sometimes erroneously listed in seed catalogues as "Didiscus caerulea," this delicate Australian is often grown as a garden decora tive. It is a close relative of the European Queen-Anne's-Lace (Daucus carota), which is now a common weed in our vacant lots and old fields.