Prostanthera
(from prostithemi, to append, and anthera, an anther; alluding to the connectives of the anthers being spurred beneath). Australian Mintbush or Mint-tree. Including Chilodia. ORD. Labiatae. An Australian genus comprising thirty-eight species of greenhouse shrubs or under-shrubs, studded with resinous glands, and usually strongly scented. Flowers generally white or red, shortly stalked, with a pair of bracteoles close under the calyx; calyx campanulate, the limb of two broad, entire lips; corolla tube short, dilated into a broad, campanulate throat, the upper lip of the limb broadly two-lobed, the lower three-lobed; whorls two-flowered, axillary or disposed in a terminal raceme. Nutlets ovoid, reticulately wrinkled. Leaves entire or toothed, often rather small, the upper ones conformed or reduced to deciduous bracts. The species best known, and most worth growing, are the under-mentioned. They are all shrubs. A sandy-peat soil suits them best. Plenty of drainage is at all times essential. Propagated by cuttings of the young shoots. P. cuneata (wedge-leaved). fl. all axillary, but sometimes crowded into terminal, leafy racemes; corolla white, with purple spots, twice as long as the calyx. June. l. sessile or nearly so, often crowded on the short branchlets, obovate-cuneate or almost orbicular, obtuse, entire or crenate, the margins often slightly revolute. h. 2ft.
P. empetrifolia (Empetrum-leaved). fl. axillary; corolla violet, fully twice as long as the calyx. September. l. sessile, linear, acute, entire, with revolute margins, rarely above 1/2in. long. h. 2ft. 1829. (B. M. 3405, under name of Chilodia scutellarioides.) P. lasianthos (woolly-flowered). Victorian Dogwood. fl. white, tinged with red, hairy, opposite, in pairs; throat of corolla spotted with red inside; pedicels short; racemes panicled. June. l. petiolate, usually oblong-lanceolate, rather acute, dentately serrated, 2in. to 3in. long. Branches nearly glabrous. h. 3ft. to 6ft. 1808. This species proves nearly hardy in favoured spots, and when grown against a wall. (A. B. R. 641; B. M. 2434; B. R. 143.) P. nivea (snowy).* fl. snow-white, or tinged with pale blue, rather large, axillary, the upper ones forming terminal, leafy racemes; corolla twice as long as the calyx. l. sessile, linear-terete, with incurved or involute margins, or flat when fresh, acute or obtuse, rather slender, mostly 1/2in. to 1in. long, the upper floral ones smaller. h. 3ft. to 6ft. 1866. A beautiful species (B. M. 5658.) P. rotundifolia (round-leaved). fl. purple, in short, close, terminal racemes, the lower ones sometimes in the axils of the leaves, like the stem ones. July. l. broadly ovate-orbicular or spathulate, on rather long petioles, very obtuse, entire or slightly crenulate, all less than 1/2in., and sometimes under 1/4in., long. h. 3ft. 1824.
P. violacea (violet).* fl. usually bluish-purple, in two or three pairs, forming small, terminal, compact racemes; corolla not twice as long as the calyx, and sometimes scarcely exceeding it. June. l. very small, shortly but distinctly petiolate, broadly ovate or orbicular, more or less crenate, with revolute margins, rarely exceeding two lines, and often not more than one line, long. h. 4ft. 1820. (B. R. 1072.)