Fig. 438.—Diagram of Impatiens glanduligera.
Fig. 439.—Fruit of Impatiens.
Impatiens; in Europe only I. noli-me-tangere. 225 species; especially from Asia. Several species have two kinds of flowers: small, cleistogamic, but fertile; and large, coloured flowers, which in I. balsamine (ornamental plant, E. Ind.) are protandrous and pollinated by hive-and humble-bees, as they suck the honey from the spur.
Order 6. Limnanthaceæ. The flowers are regular and differ from all the other orders in the family by having the carpels not in front of the petals, but in front of the sepals (which are valvate), and further, the loculi are nearly free individually, but with a common gynobasic style; the ovules are ascending and apotropous (anatropous with ventral raphe). The fruit is a schizocarp, with nut-like cocci.—Limnanthes (4 species; N. Am.) perhaps belongs to another family.
Order 7. Humiriaceæ. Trees and shrubs; about 20 species; Trop. Am.
Family 13. Columniferæ.
The chief characteristics of the orders belonging to this family are the ☿, regular, generally 5-merous, hypogynous flowers with 5-merous calyx, sepals united and valvate in the bud; petals 5, free (often twisted in the bud); stamens ∞ e.g.: 10, in two whorls, but one of these is more or less suppressed, often altogether wanting, or replaced by 5 staminodes, while the other (inner whorl) is generally divided more or less deeply into a large number of anther-bearing filaments. The filaments too (except Tiliaceæ) are united into a tube, which, especially in the Malvaceæ, forms a long column in the centre of the flower, surrounding the gynœceum (Figs. [445], [448]); in this case, which is the most pronounced, the filaments are united into one bundle (monadelphous), in other instances, polyadelphous. The number of carpels varies greatly (2 to about 50), but they are nearly always united and form a syncarpous multilocular gynœceum.—The vegetative characters also closely agree, the leaves are always scattered and generally stipulate; all the green portions very often bear stellate hairs, and the bark in all the 3 orders is rich in tough bast. Mucilage is often present in cells or passages.—This family is connected with the Ternstrœmiaceæ, from which it is very hard to draw a sharp line of demarcation, and it is also allied to the Cistaceæ and to the Gruinales.
Order 1. Sterculiaceæ (including Buettneriaceæ). This is, no doubt, the least modified order, and one in which the stamens occur undivided. Obdiplostemonous. The 10 stamens in two whorls are most frequently united at the base into a short tube, and have 4-locular, extrorse anthers. The calyx-stamens are nearly always simple, tooth-like staminodes, situated on the edge of the tube, or are entirely suppressed. The same relation is found, for instance, in the Ampelidaceæ and Rhamnaceæ, namely 5 stamens in front of the 5 petals; not infrequently the 5 stamens are doubled (Fig. [441]). Unisexual flowers are found in Sterculia, Cola, Heritiera. The corolla is often wanting, or developed in an unusual manner. Each loculus of the ovary (generally 5) always contains more than one ovule. Fruit a capsule. Androgynophore often present (Helicteres; Sterculia, etc.).
Hermannia, Mahernia, Melochia, etc., have flat petals with twisted æstivation; 5 undivided stamens, which usually are but slightly united at the base, and most frequently, without staminodes. Thomasia; Helicteres; Sterculia (free follicles).—Theobroma, Rulingia, Buettneria, Commersonia, Guazuma, etc., have petals concave at the base, and terminating in a limb abruptly bent back, and at the boundary between them most frequently ligular outgrowths, as in certain genera of the Caryophyllaceæ; stamens 5–15–∞, anthers at the edge of a short tube and 5 linear staminodes (Fig. [441]).—The Cocoa-tree (Theobroma), (Fig. [440]) bears large, reddish-yellow, berry-like fruits, resembling short cucumbers, but ultimately becoming leathery to woody; in each of the 5 loculi are 2 (apparently only 1) rows of horizontal, oily seeds, as large as almonds. Cotyledons large, thick, and irregularly folded. Endosperm absent (Fig. [442]).