Part 42

=1.= _Parnassia_ (about 14 species; _P. palustris_, Grass of Parnassus). The flower is slightly perigynous, and has S5, P5, 5 fertile sepal-stamens, and 5 petal-stamens, which are developed as barren staminodes, palmately-lobed, and (3–) 4 carpels united in a 1-locular ovary with (3–) 4 parietal placentæ. Capsule.--~Protandrous. The flower has a slightly oblique plane of symmetry, which is especially shown during its development and in the order of sequence in which the anthers dehisce: originally they lie closely round the gynœceum; the anthers dehisce extrorsely, first the one which is placed opposite the most external sepal (the 2/5 arrangement is very distinct in the calyx), the filament elongating so that the anther lies over the ovary, and this is followed successively by the 4 others in a zig-zag line; the filaments bend backwards after the pollen is shed and the anthers drop off, and the stigmas are not developed until this is completed. The barren stamens are palmately divided into an uneven number (7, 9, 11) of lobes, tapering from the centre towards the edge, and bearing apparently glandular tips; their gland-like appearance is supposed to allure flies to visit the flower, or they may act as a kind of fence which compels the insects to enter the flower in a certain way, and thus effect pollination; the honey is secreted on their inner side, and not by the gland-like tips.~

=2.= _Adoxa moschatellina_ (Moschatel). This is a perennial, creeping herb; the horizontal rhizome has an unlimited growth, and bears, in a _scattered_ arrangement, both foliage-leaves, and white, fleshy scale-leaves. The aerial stem bears 2 opposite foliage-leaves and a capitate inflorescence of 5 flowers, 4 placed laterally (in opposite pairs) and 1 terminally. The flower is semi-epigynous, the calyx gamosepalous, corolla absent. The stamens are divided to the base, so that each filament bears a bilocular anther. The style is free, deeply cleft. The _terminal_ flower has 2 bracteoles, 4 sepals, 4 stamens, cleft to the base, and a 4-locular ovary. The bracts of the _lateral_ flowers are displaced on the flower-stalk, as in _Chrysosplenium_, and united with the 2 bracteoles into a kind of 3-leaved involucre; these flowers have 5 sepals, 5 split stamens with 2-locular anthers, and a 5-locular ovary. 1 pendulous ovule in each loculus. Fruit a _drupe_, green-coloured, with 1–5 stones.--This plant, which would perhaps be best placed in a special order, has also been classed with the Araliaceæ and Caprifoliaceæ.

The following are also allied to this order: _Escalloniaceæ_ (arborescent plants with simple, scattered, leathery leaves), _Cunoniaceæ_ (arborescent with opposite leaves), _Cephalotaceæ_ (with pitcher-like, insect-catching leaves; Australia; Fig. 489) and _Francoaceæ_. These have respectively 85, 107, 1 and 3 species.

Order 3. =Ribesiaceæ= (=Currants=). 5-stamened Saxifragaceæ with epigynous flowers.--Moderately sized shrubs with _scattered_, stalked and palminerved, and generally palmilobed leaves, with a large leaf-sheath. The flowers (Figs. 490, 491), most frequently borne in _racemes_, are regular, _epigynous_, and have often, _above the ovary_, a cup- or bell-shaped, or tubular prolongation of the receptacle, on which the sepals, petals and stamens are situated; they have 5 sepals (often large, coloured), 5 _small_, free petals, only =5= stamens (opposite the sepals) and a =2=-carpellate gynœceum with a _unilocular_ ovary and 2 _parietal_ placentæ bearing many ovules. The fruit is a _berry_, whose seeds have a fleshy and juicy outer covering (Fig. 492). ~In some species, for example _Ribes grossularia_, there is found an unbranched, or a 3–5-branched spine, very closely resembling the spiny leaves of the _Berberis_, but which, however, are emergences springing from the base of the petiole. _Ribes_ has two kinds of branches: long-branches and dwarf-branches, the latter alone bearing the flowers.~--_Ribes_ (Figs. 490–492). The blades of the leaf are folded or rolled together in vernation. _R. alpinum_ is diœcious.

75 species; especially from the N. Temp. regions (especially N. Am.).--The receptacle secretes honey on its inner surface. The Gooseberry-flower is slightly protandrous, others are homogamous; insect-and self-pollination are found. The following are FRUIT BUSHES: _R. nigrum_ (Black Currant), _R. rubrum_ (Red Currant), _R. grossularia_ (Gooseberry), originating in Northern Europe and Asia. ORNAMENTAL BUSHES: the North American _R. aureum_ (Golden Currant) and _R. sanguineum_ (Blood-red Currant), etc.

Order 4. =Hydrangeaceæ.= Shrubs, with simple, opposite leaves, without stipules; flowers generally epigynous, 4–5-merous (Fig. 493).--_Hydrangea_ (_H. hortensia_, etc.). Shrubs from N. Am. and E. Asia; corolla often valvate. The inflorescence, as in the case of the inflorescence of _Viburnum opulus_ (Guelder Rose), has often irregular, large, but barren flowers at the circumference, whilst the others are much smaller, regular and ☿; the barren flowers are mostly 4-merous; in these cases it is the calyx which is large and petaloid, while the other parts of the flower are more or less suppressed. The branches of the inflorescence appear to be partially devoid of floral-leaves, since they are displaced upon the main axis.--_Philadelphus_; racemes (with terminal flower), sepals 4 (valvate), petals 4 (twisted), stamens many, and carpels 4 (opposite the petals), forming a 4-locular ovary. The numerous stamens (20–30) occur by the splitting of the sepal-stamens and are often therefore placed in distinct bundles. Fruit a capsule. _Ph. coronaria_ (Syringa, Mock Orange-blossom), from S. Eur., is a common ornamental shrub, as also is _Deutzia_ (Fig. 493) from N. Am. and E. Asia. The latter has S5, P5, A5 + 5, G3.--About 70 species.

Order 5 (?). =Pittosporaceæ.= This order has its home especially in Australia (90 species). The flower has S5, P5, A5 (episepalous), G2 (3–5), most frequently a unilocular ovary with many ovules in 2 rows, borne on 2 parietal placentæ, or a bilocular ovary. Some have berries, others capsules. _Pittosporum, Citriobatus, Sollya, Billardiera._

Order 6. =Hamamelidaceæ.= Flowers more or less epigynous, with S4, P0 or 4, 4 fertile sepal-stamens, and 4 barren petal-stamens, bilocular ovary with 1–2 ovules in each loculus. Fruit a capsule. _Hamamelis_: one species in Japan and one in N. Am. _Fothergilla._ _Liquidambar_: monœcious; flowers in capitula or spikes; ♂-flowers without perianth, stamens indefinite; ♀-flower: slight perianth, 2-locular ovary with many ovules. OFFICINAL: “Styrax-balsam,” which is obtained by boiling the bark of _Liq. orientalis_, from Asia Minor. _Liquidambar_ and _Parrotia_ are found as fossils in the Upper Oligocene; _Hamamelis_ perhaps in the Chalk.

Finally two orders with very reduced flowers are included in this family.

Order 7. =Platanaceæ.= Trees, with large, scattered, palminerved and lobed leaves, and ochreate stipules; the buds are concealed in a hollow at the base of the petiole. The bark falls off in large scales. ♂-and ♀-flowers (monœcious) in crowded, spherical inflorescences which are placed at wide intervals on a terminal, thin, and pendulous axis. The flowers have an insignificant calyx and corolla; the ♂-flower has few stamens; ♀-flower, perigynous, with 4 free carpels, 1 _pendulous_, _orthotropous_ ovule in each. Fruit a nut; endosperm absent. 5 species; frequently grown in avenues and parks. _P. occidentalis_ (N. Am.); _P. orientalis_ (W. Asia.).

Order 8. =Podostemaceæ.= Aquatic plants, especially in swiftly running water, with somewhat of an Alga-like, Moss-like, or thalloid appearance; they show themselves in many ways to be adapted to their mode of life and situations (having a dorsiventral creeping stem, the flowers sunk in hollows, a formation of haptera upon the roots, and thalloid assimilating roots and thalloid stems, etc.). Tropical; 100 species.

Family 20. =Rosifloræ.=

The leaves are scattered, stipulate, or have at least a well developed sheath, which is generally prolonged on each side into a free portion (“adnate stipules”). The flowers are regular, _perigynous_ or _epigynous_. Calyx and corolla 5 (-4)-_merous_ with the usual position. The corolla is always polypetalous. The stamens are present in very varying numbers (5–∞) and position, but _always_ placed in 5-_or_ 10-_merous whorls_; they _are frequently_ 20 in 3 whorls (10 + 5 + 5; see Figs. 494, 502, 505); the nearer they are placed to the circumference, the longer they are; they are generally _incurved in the bud, or even rolled up_. The number of the carpels is from 1–∞; in most cases all are _individually free_ (syncarp), and when they are united it is in every case with the ovaries only, whilst the _styles_ remain more or less _free_ (_Pomaceæ_, species of _Spiræa_). The _seeds_ have a straight embryo, and usually no endosperm.

The perianth and stamens are most frequently _perigynous_ on the edge of the widened receptacle; its form varies between a flat cupule and a long tube or a cup (Figs. 495, 496, 498, 499, 500); the carpels are situated on its base or inner surface, in some instances on a central conical elongation of the floral axis (Fig. 496). The carpels in _Pomaceæ_ also unite more or less with the hollow receptacle, or this grows in and fills up the space between the carpels, so that a more or less epigynous flower is formed (Fig. 504).--The following numbers of _stamens_ occur: 5, 10 (in 1 whorl), 15 (10 + 5), 20 (10 + 5 + 5), 25 (10 + 10 + 5), 30-50 (in 10-merous whorls)--compare the diagrams. The theoretical explanation of this relation of the 10-merous whorls and their alternation with the 5-merous whorls is not definitely determined; a splitting of the members of the 5-merous whorls may be supposed, but the development shows no indication of this, and it is not supported in any other way. Several genera have “_gynobasic_” styles, that is, the style springs from the base of the ovary (Fig. 497 _A_, _B_).

The Rosifloræ are on one side closely related to the Saxifragaceæ (especially through _Spiræa_) from which it is difficult to separate them, and to the Myrtifloræ; on the other side they are allied, through the Mimosaceæ with the large number of stamens, and through the Amygdalaceæ with its single carpel, to the Leguminosæ. The family begins with forms which have many-seeded follicles, and passes on the one side to forms with nuts and drupes in perigynous flowers, and on the other side to the Pomaceæ.

Order 1. =Rosaceæ.= Herbs or shrubs, generally with compound leaves and persistent (adnate) stipules, flower _perigynous_, _gynœceum formed of many free_ (therefore oblique) _carpels, syncarps_ with fruitlets of various kinds. The exceptions are noted under the genera.

=1.= SPIRÆEÆ (Fig. 495) has 2–many ovules in each ovary, while in the other groups there is generally only 1, and never more than 2 ovules in each loculus. There are generally 5 _cyclic_ carpels and the fruit is 5 _follicles_, which are not enclosed by the receptacle. The majority are shrubs. Stipules are often wanting.--_Spiræa_ (Meadow-Sweet). The flowers are generally borne in richly flowered inflorescences of various forms. The carpels, in some species, unite together and form a _simple_ gynœceum with free styles (an approach to the _Pomaceæ_).--~Closely allied to _Spiræa_ are the East Asiatic shrubs: _Kerria japonica_, which has solitary flowers, in this country nearly always double (the fruit a nut), and _Rhodotypos kerrioides_ which has opposite leaves, a remarkable feature among the Rosifloræ; it has a 4-merous flower, a well developed disc inside the andrœcium, and a drupe. Closely allied also is _Gillenia_ (N. Am.) differing chiefly in the ascending ovules, _Spiræa_ having pendulous ovules, and a more tubular receptacle.~

The groups _Quillajeæ_ and _Neuradeæ_ form a transition from _Spiræa_ to _Pomaceæ_. In the first group, which contains only trees or shrubs with generally simple leaves, the carpels are either free or united (into a capsule); in the second the receptacle unites with the carpels, which are themselves often united together; in this case, too, the fruit is a capsule. _Quillaja_ (S. Am.); _Exochorda_ (China).

=2.= POTENTILLEÆ (Figs. 494, 496, 497). The flower has an “_epicalyx_” (Fig. 494 _C_) alternating with the sepals and formed by their stipules which are united in pairs, and hence its leaves are often more or less deeply bifid. The receptacle is cupular and often quite insignificant. The sepals are valvate in the bud. The large number of fruitlets are _achenes_, borne on a well-developed convex portion of the receptacle (~the Ranunculeæ resemble the Potentilleæ, but have no epicalyx, no enlarged receptacle, and spirally-placed stamens~). Most of the species are herbs with dichasial inflorescences, often arranged in racemes.--_Potentilla_ (Cinquefoil). The achenes are borne on a _dry_, hairy receptacle; the style is situated towards the apex of the ovary, and is not prolonged after flowering. Herbs with digitate, in some, however, pinnate leaves, and generally yellow flowers.--_Comarum_ (Fig. 494) (Marsh Cinquefoil) forms, by its fleshy-spongy receptacle, a transition to the next genus.--_Fragaria_ (Strawberry) (Fig. 496). The receptacle becomes finally fleshy, coloured, and falls off (biologically it is a berry); the numerous fruitlets (drupes with thin pericarp) have basal styles (Fig. 497); leaves trifoliate; long, creeping runners.--_Geum_ (Avens) has a terminal style which after flowering elongates into a long beak, with the apex (after the uppermost part has been thrown off) bent back into a hook, thus furnishing a means of distribution for the fruits. Leaves pinnate.--~_Dryas_ comprises 3 Arctic or Alpine species with simple leaves and solitary flowers, the calyx and corolla 8–9-merous, the fruit resembles that of _Geum_, but the styles become still longer and feather-like (a flying apparatus).~

=3.= RUBEÆ. _Rubus_ (Bramble) has the same form of receptacle as the _Potentilleæ_, but _no epicalyx_; _the fruitlets are drupes_, not enclosed by the persistent calyx. Most frequently shrubs or undershrubs with prickles (emergences), glandular bristles and compound leaves. In the Raspberry (_R. idæus_) the fruitlets unite together and detach themselves from the receptacle.

=4.= ROSEÆ. _Rosa_; the receptacle is hollow, ovoid and contracted beneath the insertion of the calyx (Fig. 498), ultimately _fleshy_ and _coloured_; it encloses a large number of fruitlets which are achenes as hard as stones (“hip,” biologically a berry).--Shrubs with imparipinnate leaves and adnate stipules. ~The sepals show clearly the order of their development (a divergence of 2/5), the two outer ones on both sides are lobed, the third one on one side only, and the two last, whose edges are covered by the others, are not lobed at all. _Prickles_ (emergences) are generally present and in some species are placed in regular order, being found immediately below each leaf (usually two) although at somewhat varying heights.~

=5.= AGRIMONIEÆ. The receptacle is more or less cup- or bell-shaped, and almost closed at the mouth; it is persistent and envelopes the _nut-like fruitlets_, but is _dry_, and in some species hard, the fruitlets being firmly attached to it. In biological connection with this the number of the carpels is generally only 1 or 2, and the whole becomes a _false nut_ (Fig. 500). Herbs.--_Agrimonia_ (Agrimony; Figs. 499, 500); the perianth is 5-merous, stamens 5–20. The receptacle bears externally, on the upper surface, a number of hooked bristles which serve as a means of distribution for the 1–2 achenes which are enclosed in it, and hence the entire flower finally falls off. The inflorescence is a long upright raceme. ~These bristles are arranged in whorls of 5 and 10, of which the uppermost alternate with the sepals.~--_Alchemilla_ (Ladies-mantle; Fig. 501) has 8 green perianth-leaves in two whorls (some authorities consider the four outer as an epicalyx, and the flower therefore apetalous), and 4 stamens _alternating with the innermost whorl_. There is only one carpel with a _basal_ style and capitate stigma. The flowers are small and greenish, the filaments jointed. The anthers open by one extrorse cleft. The leaf-sheath entirely envelops the stem; the leaves are palminerved. _A. aphanes_ has often only 1–2 stamens. ~The following genera, with 4-merous flowers borne in short spikes or capitula, are allied to this group. _Sanguisorba_ has entomophilous, ☿-flowers with 4(-20) stamens, 1 carpel; stigma papillose.--_Poterium_; spike or capitulum, the uppermost flowers are ♀, the lowermost ♂, and some intermediate ones ☿ (the order of opening is not always centripetal); S4, P0, A20–30, G2, the long styles having brush-like stigmas (wind-pollination). Leaves imparipinnate.~

POLLINATION. A yellow ring on the inner side of the receptacle, inside the stamens, serves as a nectary when any honey is formed; this, for instance, is not the case in _Rosa, Agrimonia_, _Spiræa ulmaria_, _S. filipendula_, _S. aruncus_, etc., to which the insects (especially flies and bees) are allured by the quantity of pollen. Homogamy and slight protogyny are frequent, in many instances self-pollination also is finally possible. _Poterium_, with the long-haired stigma, is wind-pollinated.--About 550 (1100?) species, especially in northern temperate regions.--USES. OFFICINAL: the petals of _Rosa centifolia_ and _gallica_, the fruits of the Raspberry (_Rubus idæus_), the rhizome of _Geum urbanum_, the flowers of the Koso-tree (_Hagenia abyssinica_ or _Brayera anthelmintica_).--The bark of _Quillaja saponaria_ (Chili) is used as soap and contains _saponin_. “Attar of Roses” from _Rosa damascena_, _centifolia_ and other species, especially from the southern slopes of the Balkans. Many species and varieties of Roses are ORNAMENTAL plants: from S. Europe, _Rosa lutea_ (the Yellow Rose), _R. gallica_ (the French Rose) and _R. rubrifolia_; from W. Asia, _R. centifolia_, of which the Moss Roses (_R. muscosa_ and _cristata_) are varieties, and _R. damascena_; from India and N. Africa, _R. moschata_ (the Musk Rose); from China, _R. indica_ (Tea Rose) etc., besides the native species and the varieties which have been derived from them. In addition, _Kerria japonica_, species of _Potentilla_, _Rubus odoratus_ from N. Am., and many species of _Spiræa_ from South-eastern Europe and N. Am. ESCULENT: the “hips” of _R. mollissima_, _R. pomifera_, etc.; the fruits of _Rubus_-species: Raspberry (_R. idæus_), Cloudberry (_R. chamæmorus_), Blackberry (_R. fruticosus_), etc.; of _Fragaria_-species (_F. vesca_, _collina_, _grandiflora_, etc).

Order 2. =Amygdalaceæ.= Trees or shrubs with rosaceous flowers; leaves simple with caducous stipules; a regular, _perigynous_ flower, the receptacle being partly thrown off by a circular slit; sepals 5, petals 5, stamens 20–30; _gynœceum simple, formed of 1 carpel_ (hence oblique, Fig. 502), with terminal style and 2 pendulous ovules, ripening into a _drupe_ (Fig. 503).--The leaves are penninerved and frequently have _glands_ on the stalks and edges; _thorns_ (modified branches) often occur, _i.e._ dwarf-branches, which, after producing a few leaves, terminate their growth in a thorn (_e.g._ _Prunus spinosa_). ~The vernation of the _foliage-leaves_ varies in the different genera; in the Almond, Peach, Cherry, and Bird-Cherry they are folded; in the Apricot, Plum, Sloe and Bullace, rolled together. In some the flowers unfold before the leaves (_Amygdalus_, _Armeniaca_). That the gynœceum is formed of 1 carpel is evident in this as in other instances (_e.g._ in the Leguminosæ, which are closely related to this order), from the fact that the carpel is oblique, and has only one plane of symmetry, and similarly in the fruit there is a longitudinal groove on one side which indicates the ventral suture. It is only exceptionally that both ovules are developed. In abnormal instances more than 1 carpel is developed.~

=A.= FRUIT HAIRY: _Amygdalus_ (_A. communis_, Almond-tree) has a dry pulp which is detached irregularly, when ripe, from the wrinkled, grooved, ovoid and somewhat compressed stone.--_Persica_ (_P. vulgaris_, Peach-tree) differs from the Almond in having a juicy pulp, not detachable from the stone, which is deeply grooved and has pits in the grooves (Fig. 503). (~The name of the genus is derived from Persia, though it is a native of China.~).--_Armeniaca_ (_A. vulgaris_, Apricot) has a hairy, velvety fruit, but the stone is smooth and has two ribs along one of the edges; the pulp is juicy. (~The generic name has been given on the incorrect assumption that it was a native of Armenia; its home is China.~)

=B.= FRUIT GLABROUS (_i.e._ without hairs): _Prunus_ (Plum) has a glabrous fruit with bluish bloom; the stone is compressed, smooth or wrinkled. The flowers are borne solitarily or in couples, and open before or at the same time as the leaves; they are borne on shoots without foliage-leaves.--_Cerasus_ (Cherry) has a glabrous, spherical fruit, without bloom, and a spherical stone. The flowers are situated in 2–many-flowered umbels or racemes, and open at the same time as the leaves or a little before them. ~_Long-stalked_ flowers in _umbels_ are found in _C. avium_ (Wild Cherry), _C. vulgaris_ (the cultivated Cherry, from Western Asia); _racemes_ at the apex of leaf-bearing branches and small spherical fruits are found in _C. padus_ (Bird Cherry), _C. virginiana_, _C. laurocerasus_ (Cherry-laurel), _C. mahaleb_.~