Fig. 315.—Diagram of a Zingiberaceous flower (Kæmpferia ovalifolia): b bract; v bracteole; k calyx; p1, p2, p3 the petals; sst, lateral staminodes (“wings”); lab labellum (formed of two staminodes); st the fertile stamen; * position of suppressed stamen. The ovary is in the centre of the diagram.]
Order 2. Zingiberaceæ. Perianth most frequently divided into calyx and corolla. Calyx gamosepalous. Only 1 fertile stamen (the posterior, Fig. [315], belonging to the inner whorl) with quadrilocular anther, which encloses the style in a furrow; the 2 stamens in the outer whorl are staminodes, the median one (the anterior) is wanting. The 2 lateral staminodes of the inner whorl form the “labellum” (Fig. [315] lab), which usually is the largest segment of the flower, and is often bilobed. Ovules many. The fruit in some is a leathery, 3-valved capsule, with loculicidal dehiscence; in others it is more or less berry-like and indehiscent, or irregularly dehiscent. Straight embryo.—The aerial stem is seldom developed to any extent, and the inflorescences, which are (compound) spikes or racemes, often with coloured floral-leaves, spring in some (e.g. Zingiber officinale) directly from the rhizome. The leaves are arranged in two rows.—The ovary in a few instances (Globba and others) is unilocular, with 3 parietal placentæ.
They are perennial herbs with fleshy and tuberous rhizomes, which are used as condiments and in medicine on account of their pungent and aromatic properties and also for starch, dyes, etc. Officinal: rhizomes of Zingiber officinale (Ginger, unknown wild, but cultivated generally in the Tropics), of Curcuma longa (Turmeric, a dye, E. India) and C. zedoaria, of C. angustifolia and others (as E. India Arrowroot), of Alpinia officinarum, China (galangal). “Preserved Ginger” from Alpinia galanga. Similar aromatic materials (volatile oils) are present also, for example, in the fruits; Cardamom fruits and seeds (from Elettaria cardamomum, China, seldom from E. major).
315 species; Tropics, preponderating in the Eastern Hemisphere, India, and especially S. Asia, whence all the aromatic species originate; they are now commonly cultivated in the Tropics. Some are ornamental plants in greenhouses, e.g. Hedychium, Costus, etc. Globba (with axillary buds in the inflorescence, as in Ficaria), Renealmia, Kæmpferia.
Fig. 316.—Flower of Canna: f ovary; pa calyx; pi corolla; l labellum; st stamens; an anther; g stigma; α and β staminodes.
Order 3. Cannaceæ. American herbs without aromatic properties. Flowers asymmetric (Fig. [316]). Calyx polysepalous. The stamens are petaloid (Fig. [316] st) and barren with the exception of one (the posterior), which bears on one of its edges a bilocular anther; another, which is especially large and coloured, is termed the labellum. The style is compressed and leaf-like, with a small stigma at the apex. Ovules numerous in the 3 loculi. The capsule is furnished with warts or soft prickles. Embryo straight.
Canna (30 species; Trop. Am.). The inflorescence is a terminal spike with 2-flowered unipared scorpioid cymes in the axils of the floral-leaves. Ornamental plants: Canna indica, etc.
The diagram of the andrœcium of the Cannaceæ and Marantaceæ may be represented in the following manner (calyx, corolla and gynœceum being omitted):—
| Cannaceæ. | Marantaceæ. |
| w w | w w |
| st | st |
| w lab | wi c |
| * | * |