Part 64

FIG. 462.--♂-flower with the 2 bracteoles and the solitary stamen.

FIG. 463.--♀-flower.

FIG. 464.--Longitudinal section of the ripe fruit.]

Order 3. =Callitrichaceæ.= Aquatic plants, growing at the bottom of shallow water, with opposite, simple, undivided, entire, exstipulate leaves, which are generally crowded and form a rosette in the apex of the branches. The flowers are unisexual (monœcious) and borne singly in the leaf-axils; they have no perianth, but are provided with two delicate bracteoles; the ♂-flowers consist of only 1 terminal stamen (Fig. 462); the ♀-flowers of a bicarpellate gynœceum (Fig. 463) which is originally 2-locular, but later on becomes 4-locular, as in the case of the gynœceum of the Labiatæ, by the formation of a false partition-wall; in each loculus there is 1 pendulous ovule with the micropyle turned outwards. Fruit a 4-partite schizocarp (Fig. 464). 25 species.--Callitriche.

Order 4 (?). =Empetraceæ.= 4 species. Empetrum; E. nigrum (Crowberry) is a heather-like, moorland, evergreen undershrub with linear leaves, having a deep groove closed with hairs, on the under side. The erect ovules show the greatest deviation from the Euphorbiaceæ. Diœcious (and ☿); S3, P3; in the ♂-flower, 3 stamens; in the ♀-flower, a 6–9-locular ovary. Fruit a drupe.

Family 15. =Terebinthinæ.=

The diagram of the flower (Figs. 465–467) is the same as in the Gruinales, namely S, P, A2 and G in whorls of 5 (less frequently 3, 4, 6, 8), and the same modifications also occur with the suppression of the petal-stamens, etc. But a ring or sometimes cup-like glandular structure (disc) is found between the andrœcium and the gynœceum (Figs. 465, 466). The flowers similarly are regular, hypogynous, ☿ and polypetalous, though exceptions are found to all these characters: thus, for example, united sepals and petals frequently occur, and, in some orders, unisexual flowers by the suppression of one sex. In most cases the flowers are small, greenish-yellow, and arranged in paniculate inflorescences. The carpels (most frequently 5) are free in a few, but generally united into a multilocular gynœceum; rarely more than 1 or 2 ovules in each loculus. The gynœceum in the Anacardiaceæ is so reduced that it has only 1 fertile loculus with 1 ovule.--The ovules are epitropous, i.e. anatropous with outward-turned raphe (except the Anacardiaceæ).--The majority of the species are trees and shrubs with scattered, often compound (pinnate) leaves without stipules, and as in addition they frequently contain aromatic, especially turpentine-like substances, they assume a certain resemblance to the Walnut trees, and were formerly classed with them mainly on this account. In a series of genera the volatile, scented oils are found in special glands in the bark of the branches and in the leaves, in the latter case appearing as pellucid dots. This family includes several orders which are somewhat difficult to distinguish from each other.

Order 1. =Connaraceæ.= This order forms the connecting link between Terebinthinæ and Rosifloræ (Spiræa) as well as Leguminosæ, with which they are sometimes classed. The flowers have 5 5-merous whorls; 2 ovules in each loculus; micropyle turned upwards. Fruit a follicle, rarely a collection of follicles. Seed with aril. Shrubs with scattered (most frequently pinnate) leaves, without stipules. 170 species. Tropical.

Order 2. =Meliaceæ.= Trees and shrubs with scattered, often pinnate leaves without pellucid dots and exstipulate; the leaflets are nearly always entire. Flowers small in paniculate inflorescences. Calyx and corolla 4–5-merous; 2 whorls of stamens; 3–5 carpels in the gynœceum. A very characteristic feature is the union of the filaments into a tube, on the edge of which stipule-like teeth are often found. There are most frequently 2 ovules in the loculi; fruit a capsule with many winged seeds in Swietenia (Mahogany tree; Trop. Am.), Cedrela, etc.; berries in others. The wood of Cedrela is used for making cigar boxes. 550 species; tropical.

Order 3. =Rutaceæ.= Leaves glandular with pellucid dots. The type is the same as that of the family. Flowers 4–5-merous. The ovary is most frequently 4–5-grooved. Disc well pronounced, often appearing as a “gynophore.” The majority are shrubs with alternate or opposite, compound, more rarely simple, leaves.

=A.= The ovary is deeply 2–5-cleft with basal styles which are more or less united; the carpels in some genera are entirely free (groups 1, 2). The fruit is capsular and most frequently dehisces like follicles along the ventral suture or septicidally, so that a horn-like internal layer (endocarp) separates elastically from the external layer.

=1.= ZANTHOXYLEÆ. Zanthoxylum; Choisya; Evodia.

=2.= BORONIEÆ. Australia.--Correa.

=3.= DIOSMEÆ. Heather-like shrubs; Africa.--Diosma, Coleonema, Empleurum and Barosma. OFFICINAL: Barosma crenulata and betulina, “broad Buchu leaves” (B. serratifolia and Empleurum serrulatum, “narrow Buchu-leaves”).

=4.= RUTEÆ. Ruta (Figs. 465–467) graveolens is an herbaceous, glaucous, strongly smelling plant with bipinnate leaves and yellow flowers; the terminal flower is 5-merous, the others 4-merous (S. Eur.).--Dictamnus; zygomorphic flower. ~The individual carpels of the fruit separate from each other, and dehisce like follicles, upon which the internal layer is detached elastically and springs out, carrying the seeds with it. Several species are ornamental plants.~

=5.= CUSPARIEÆ. American. Flowers often zygomorphic with gamopetalous corolla; stamens 5.--Ticorea; Galipea (G. officinalis; S. Am.; “Cortex angosturæ”); Cusparia; Almeidea.

=B.= The ovary is entire or only slightly grooved; the style is terminal, undivided. The fruit is most frequently a drupe or berry.

=6.= TODDALIEÆ. Ptelea; winged fruit. The buds are enclosed in the leaf-sheath. Skimmia; Phellodendron.

FIG. 468.--Branch with compound leaves.

FIG. 469.--Transverse section of fruit.

FIG. 470.--Flowers (after the removal of the petals).]

=7.= AURANTIEÆ, ORANGE GROUP. Fruit a berry with a leathery external layer.--The most typical flower is found for example in Limonia: S5, P5, A5 + 5, G5 (2–5).--Citrus has 4–5–8-merous flowers, a gamosepalous, dentate calyx, free petals, one whorl of stamens which are split irregularly into several bundles (Fig. 470). The fruit is a multilocular berry provided with a thick, tough, outer layer. The juicy pulp, which fills up the loculi and envelopes the seeds, is formed from many large-celled, juicy hair-structures which arise on the inner side of the walls of the loculi and by degrees entirely fill them up; the dissepiments remain thin, and form the partitions so easily separating from each other (Fig. 469). The seeds in many instances are remarkable for containing several embryos. The blade of the leaf is separated from the frequently winged stalk by a node (and hence is a compound leaf with only the terminal leaflet developed?) (Fig. 468); in other genera, as Triphasia, there is a fully developed trifoliate leaf. Thorns are frequently developed.--~The species of this genus, which is a native of the warmer parts of S. E. Asia, are very hard to separate. The differences are found in the forms of the fruit, the leaves and the leaf-stalks, and in the number of stamens. Citrus medica, “Cedrat” (Ind.); C. limonum, “Citron,” “Lemon” (introduced into Italy in the 3rd to 4th century). OFFICINAL: the fruits and essential oil of Lemon. C. aurantium from E. Asia, the Orange (introduced into Italy in the 14th century). C. vulgaris (Fig. 468), Bitter Orange (introduced into Europe at the time of the Crusades); the unripe Bitter Oranges, and peel of the Bitter Orange is officinal; it is from the flowers of this species especially that the essence of Neroli is made. C. limetta, C. bergamia, Bergamot; essence of Bergamot is officinal. C. decumana, Pomalo, a native of the Islands of the Pacific. About 780 species; chiefly tropical.~

Order 4. =Burseraceæ.= Fruit a drupe; 1–5 stones. The bark, as well as the other parts, contain strong aromatic resins and balsams, and hence several species are used: the Myrrh tree, Commiphora (Balsamodendron) from Arabia and Africa; OFFICINAL: Myrrha (Commiphora myrrha). Mecca-balsam from C. opobalsamum, Arabia; E. Africa. The Incense-tree (Boswellia) from the same parts of the globe and E. India. The incense of B. carteri is medicinal (Frankincense). The resin (Elemi) of Protium-species is officinal, and is used technically for varnish (S. Am.). Takamahaka-resin from Elaphrium (S. Am.) Protium (Icica); Amyris (1 carpel). 270 species; tropical.

Order 5. =Zygophyllaceæ.= The majority have opposite, pinnate leaves with stipules. Leaves without pellucid dots. The filaments have a scale on the inner side. The most important is Guaiacum officinale (West India), the wood (Lignum Vitæ) of which is very hard and heavy, this wood and Gum-guaiacum are officinal. Others have a peculiar repulsive smell and taste: the Creosote shrub (Larrea mexicana) and Zygophyllum simplex. Tribulus terrester is a common weed in S. Europe. Fagonia. Peganum harmala (South of Russia) yields a red dye.--110 species; especially in the Tropics; several species in sandy deserts. Nitraria.

Order 6. =Simarubaceæ.= This order is distinguished by the abundance of bitter substances which it contains (Quassine) especially in the bark and the wood. The wood of Quassia amara (Guiana, Antilles) is officinal; Picraena excelsa yields Jamaica Quassia; the bark of Simaruba, Simaba-species and others is used. Ailanthus glandulosa is a garden plant (pinnate leaves, winged fruit).--110 species. Tropical.

Order 7. =Ochnaceæ.= Flowers diplostemonous, 5-merous. The unilocular ovaries, which are individually free, project considerably into the air around the gynobasic style; 1 ovule in each loculus; the fruitlets are drupes. Shrubs; leaves alternate, with stipules. Ochna; Ouratea.--160 species; tropical; especially American.

Order 8. =Anacardiaceæ.= The ovary rarely contains more than 1 ovule, even though there be several loculi and several carpels; in Anacardium all the 10 stamens except one become suppressed. Resin passages.--Anacardium. The most peculiar feature is the development of the flower-stalk into a fleshy body about the form and size of a pear (A. occidentale from Trop. Am. and A. orientale from E. Ind.) which bears the kidney-shaped nut (the so-called “Cashew-nut”) on its apex. Mangifera indica (the Mango-tree, from E. Ind.) is cultivated in several tropical countries on account of its delicious drupe. Similarly, species of Spondias (S. dulcis, Pacific Islands, S. lutea). Several species of Rhus are ornamental shrubs in this country, for instance, R. typhina (N. Am.), R. cotinus (the Wig-tree, the barren flower-stalks of the panicles being feather-like and hairy); R. toxicodendron (Poisonous Sumach, from N. Am.) is poisonous. Chinese galls are produced by the sting of a leaf-louse (Aphis chinensis) on R. semialata (China), and Japanese wax is from the seeds of R. succedanea (Japan). Considerable quantities of Sumach (R. coriaria) are used in tanning and as a black dye. OFFICINAL: the mastic resin of Pistacia lentiscus (the Mastic-tree, from the Mediterranean). The fruits of Pistacia vera (Syria) are edible; P. terebinthus and others yield turpentine.--450 species; tropical.

Order 9. =Icacinaceæ.= Flowers 4–5-merous; haplostemonous; receptacle convex or cup-like surrounding the gynœceum; in the (single) loculus of the ovary, 2 anatropous, pendulous ovules.--200 species; tropical.