Part 41

Family 17. =Frangulinæ.=

The plants belonging to this family, with very few exceptions, are trees or shrubs. The leaves are usually simple; stipules may be absent or present. The flowers in almost all the orders are _small, green or whitish_; they are _always regular_, 4-_or_ 5-_merous_ with 2–5 _carpels_, but never have more than 1 _whorl of stamens_, which in _Rhamnaceæ_ and _Ampelidaceæ_ are placed _opposite_ the petals (typically 5 + 5 or 4 + 4 stamens, of which however either the external or internal whorl is always wanting); hypogynous or slightly perigynous, in _Rhamnaceæ_ only strongly perigynous or epigynous; generally ☿; the calyx is inconspicuous; petals free or slightly united. Gynœceum simple; _ovary generally multilocular_; style short or entirely wanting. A _disc_ is nearly always developed in the flower, but is found sometimes inside the staminal whorl, sometimes outside it or between the stamens. The ovules are apotropous (anatropous with dorsal or ventral raphe).

Order 1. =Celastraceæ.= _Euonymus europæa_ (Spindle-tree) may be chosen as a type. It is a shrub with simple, opposite leaves and small caducous stipules. The small, greenish-yellow flowers, borne in regularly-branched dichasia, are regular, ☿, with 4 whorls, 4-(or 5-) merous in regular alternation. There is a _thick disc_ upon which the polypetalous corolla (imbricate in the bud) and the stamens are borne, with a slightly perigynous insertion. The style is short and thick; the ovary has 2 _erect_ ovules in each loculus. The fruit is a red, 4-valvate capsule with loculicidal dehiscence; the seeds are few in number, and have a large, red-yellow _aril_ (developed from the micropyle). Embryo green, in a large, fleshy, white endosperm. ~The dingy yellow flowers are generally visited only by flies and ants for the sake of the honey secreted by the disc, and while they run about on the flowers they touch the anthers and stigmas, now with one part of the body, now with another. The flower is protandrous. The stigmas are not developed till several days after the opening of the anthers.--_Celastrus_, _Cassine_, _Catha_, etc.~

38 genera; 300 species. Distributed over the entire globe, with the exception of the colder districts, and especially in the Tropics. Some are ornamental bushes (_Euonymus japonica_). The leaves of _Catha edulis_ are used by the Arabs and Abyssinians in the same way as those of _Coca_ by the Peruvians.

Order 2. =Hippocrateaceæ.= 150 species; tropical; chiefly lianes. S5, P5, A3, G3. Anthers extrorse.

Order 3. =Aquifoliaceæ (Hollies).= The genus _Ilex_ forms almost the entire order. (175 species out of 180; especially from S. Am.) They are shrubs or trees with scattered, leathery, simple leaves (in _Ilex aquifolium_, spiny) with very small stipules. The flowers are small, white, and borne in few-flowered inflorescences in the axils of the foliage-leaves; they are most frequently unisexual and diœcious. There are 4–5 sepals, petals, stamens and carpels in regular alternation; the calyx and _corolla_ have their leaves _slightly_ connate; stamens slightly adnate to the corolla; the ovary is generally almost spherical with a thick, sessile stigma (Fig. 477). This order deviates especially from _Celastraceæ_ in the _absence of the disc_ and in having only 1 (_pendulous_) ovule in each of the 4 loculi of the ovary, and in having a _drupe_ with generally 4 stones. Embryo extremely small, at the apex of the large endosperm, with the radicle directed upwards.--~3 genera.--_I. aquifolium_ (Holly) principally on the coasts of European countries; from Norway to W. Denmark, and further westward. It is a common garden shrub with stiff, shining leaves and red fruits. Several South American species contain so much _caffeine_ that they may be used as a beverage in the place of tea (_I. paraguayensis_, Paraguay tea, or Maté). The Holly does not contain caffeine.~

Order 4. =Ampelidaceæ (Vines).= Shrubs with the stem swollen at the insertion of the petioles and climbing by _tendrils borne opposite the leaves_ (Figs. 478, 479). The leaves are scattered (generally 1/2), stalked, stipulate, frequently palminerved and lobed, divided or compound. The small, greenish flowers are generally borne in paniculate _inflorescences, whose position is the same as that of the tendrils_ (Fig. 478); they are hypogynous or slightly perigynous, ☿, with 4–5 sepals, petals, stamens (which, as in the Rhamneæ, are _opposite the petals_; Fig. 480 _A_, _B_) and 2 carpels. The calyx is very small, entire, or slightly dentate; corolla _valvate_, and in some falling off as a hood, since the individual parts remain united at the summit (Fig. 480 _A_). Between the stamens and gynœceum is situated an hypogynous _disc_, with 5 lobes alternating with the stamens (Fig. 480 _A_, _B_, _E_). In each loculus of the 2-locular ovary there are 2 _erect_ ovules (_E_); the style is short or wanting. The fruit is a _berry_. The embryo is small and lies in a horny, sometimes slightly folded (ruminate) endosperm (Fig. 480 _C_, _D_).

_Vitis_ and _Ampelopsis_ (5-merous flowers); _Cissus_ (4-merous flower); _Leea_ (without stipules, corolla gamopetalous). The inflorescence in _Pterisanthes_ (E. Ind.) has a peculiar, flat, leaf-like axis, on the edges of which ♂-flowers are borne, and on the surface ♀-flowers.

The TENDRILS in Ampelidaceæ are modified branches, since they bear leaves and may be abnormally developed as branches with foliage-leaves, and finally the inflorescences are borne in the position of the tendrils, and tendrils are met with which are partly inflorescences. The explanation of the position of the tendril, namely, right opposite the foliage-leaf but without a subtending-leaf, has been much disputed. The relative positions are as follows: in _Vitis vinifera_ the following two kinds of shoots and relative positions are found (the other species deviate in one or other particular), (_a_) LONG-BRANCHES, which have 2 scale-leaves and a large number of foliage-leaves with a divergence of 1/2; opposite the lowest 3–5 foliage-leaves no tendrils are found, then follow: 2 foliage-leaves with tendrils, 1 without a tendril, 2 with and 1 without, etc., with great regularity. Buds are developed in the axils of the foliage-leaves (Fig. 479): these develop into (_b_) DWARF-BRANCHES, which commence with 1 laterally-placed scale-leaf (fore-leaf; Fig. 481 _v_) succeeded by several foliage-leaves with a divergence of 1/2 (in a plane at right angles to that of the mother-shoot), but the whole shoot is extremely small, and often dries up and drops off in the autumn, so that only the scale-leaf, _v_, with the bud (Fig. 481 _lt_{1}_) in its axil remains. This bud in the following year developes into a new long-branch, and since its leaves lie in a plane at right angles to that of the dwarf-branch, their plane coincides with that of the long-branch from which it is developed (the grandmother axis).--The tendrils no doubt may most correctly be regarded as the modified main axis which has been pushed aside by a lateral branch. The branches are then sympodia, whose successive shoots bear alternately 1 and 2 foliage-leaves: thus, on the figure there are portions altogether of 5 shoots (I.-V.), the 1-leaved ones are shaded, the 2-leaved ones are white. The following facts however are adverse to this theory: (1) the first leaf on an axillary bud is then situated 180° from the subtending leaf (_e.g._ the lowermost shaded leaf, Fig. 479, 180° from the lowermost white leaf), whilst the rule in the Dicotyledons is that it is placed only about 90° to one side. (2) The buds (Fig. 479 _K_) from which the dwarf-branches develop, must then be accessory and sister-buds to the sympodial shoots, but their first leaves have a different relative position to this, which is very peculiar, and a still more remarkable fact is that the buds, _K_, etc. are similar in structure and present in _all the axils_; thus we _only_ find accessory buds in the cases where no tendrils are opposite to the leaves, and the main bud must then be considered to be suppressed. (3) The development proves that the tendrils arise on the side of a vigorous growing-point of the stem or by its division, and do not develop, as might be expected, from the apex of the shoot. But these relations however, find their analogues and are all capable of explanation, whereas other less natural modes of explanation are opposed to them.

435 species; especially in the Tropics; they are rarer in America. In N. Am. some _Vitis_-species and _Ampelopsis quinquefolia_ are found. _Vitis vinifera_ is supposed to have originated in the districts East and South of the Caspian Sea. Wine is obtained from _Vitis_-species, especially _V. vinifera_, and “raisins,”--(the name “currants,” given to a special variety with small, seedless fruits, is derived from Corinth).--The species of _Ampelopsis_ (Virginian Creeper) are cultivated as ornamental plants.

Order 5. =Rhamnaceæ.= _The stamens are placed opposite the petals_ as in the Ampelidaceæ (Fig. 482), but the flowers are _much more perigynous or entirely epigynous_. The trees and shrubs belonging to this order have simple, most frequently penninerved leaves with stipules; frequently thorny (modified branches). The flowers are inconspicuous, sometimes unisexual (Fig. 482), and have 5 (-4) sepals, petals, stamens, and generally 3 (2–5) carpels. The calyx has _valvate_ æstivation. The petals are very _small_ (generally less than the sepals), often spoon-like, hollow, and embracing the stamens; _a disc covers the inner surface of the thalamus_ or the base of the style in the epigynous flower; gynœceum simple, with one style and one _erect ovule in each loculus_. The fruit is most frequently a _drupe_. The embryo is large, often green or yellow, with endosperm.

_Rhamnus_ (Buckthorn) has a juicy drupe with 3 (2–4) stones, surrounded at the base by the persistent portion of the receptacle; the disc is thin. _R. cathartica_ (common Buckthorn): diœcious, with opposite, serrate leaves. _R. frangula_ (Alder Buckthorn): flowers ☿, with scattered, entire leaves.--~_Ceanothus_ (N. Am., with richly-flowered inflorescences and a fruit closely resembling that of the Euphorbias). _Phylica_, _Pomaderris_ (Austr., fruit a capsule). _Zizyphus_, _Paliurus_, _Colletia_ (S. Am.) are thorny shrubs; _C. spinosa_ has thorny shoots with small, caducous leaves; the seedling has normal foliage-leaves. Others climb by tendrils as in the Ampelidaceæ, _e.g._ _Gouania_.~

475 species, 40 genera; chiefly in temperate and tropical climes. Some are medicinal plants, the bark and fruit having purgative properties (the bark of _Rhamnus frangula_ and “Cascara Sagrada” from the bark of _R. purshiana_ are officinal). The fruits and seeds of others are edible, for example, the fruits of _Zizyphus lotus_, _Z. vulgaris_, _Z. spina Christi_, etc. Green and yellow _dyes_ are obtained from the fruit of _R. cathartica_, _infectoria_ and others (Avignon grain). _Ceanothus-_, _Rhamnus-_ and evergreen _Phylica_-species are ornamental shrubs.

Family 18. =Thymelæinæ.=

Exclusively trees or shrubs with simple, entire, scattered leaves without stipules. They have a _strongly perigynous_, regular, _4-merous_ flower. The receptacle (often coloured) envelopes a simple gynœceum formed of =1= _carpel_ and with, in most cases, =1= ovule, bearing on its edge 4 (or 5) petaloid sepals and, but rarely at the same time, small, scale-like petals. The corolla is most frequently entirely wanting (and hence these plants were formerly reckoned among the Monochlamydeæ); frequently only one of the 2 whorls of stamens, which are situated on the inner side of the edge of the receptacle, is developed. The fruit is most frequently a _1-seeded_ berry or drupe, or a nut which may be falsely berry-like, the partly persistent receptacle being fleshy and enveloping it.

This family appears the most nearly allied to the Frangulinæ, especially the Rhamnaceæ, and may be considered as a further development of these in the direction of the petaloid development of the receptacle and reduction of the corolla and gynœceum, which in this instance only consists of one carpel. Another deviation is that both the whorls of stamens are present, while one of these is always wanting in Frangulinæ. They also appear to be related to the Lauraceæ (see page 391).

Order 1. =Thymelæaceæ.= The flowers are most frequently ☿ (Fig. 483). The receptacle is high, generally tubular, coloured, and bears on its edge the 4-(or 5)-merous calyx, with imbricate æstivation. The corolla is wanting or is represented by small scales. The stamens are situated on the inside of the receptacle, and number 4 + 4 (or 5 + 5); stigma capitate. 1 _pendulous ovule_ (Fig. 483 _B_), the _radicle pointing upwards_. The fruit is most frequently a berry. ~A disc is sometimes developed. Endosperm wanting or very slight.~

_Daphne_ (Spurge-Laurel, Fig. 483) has a deciduous receptacle, often coloured; sepals 4; petals absent; stamens 4 + 4. Berry.--_Gnidia_ (corolla); _Pimelea_ (2 stamens); _Thymelæa_; _Passerina_ and others.

400 species; chiefly in the warm, sub-tropical zone, especially the Cape and Australia. Only _Daphne_ and _Thymelæa_ in Europe. In the fruit and bark of some, for example _Daphne_, pungent, burning and poisonous properties are found. The bark of _D. mezereum_ (native and cultivated) and _D. laureola_ is officinal. A specially tough bast is found in some species, for example _Lagetta lintearia_ (Lace-tree, Jamaica), which is used in weaving. Some are cultivated in gardens as ornamental shrubs, especially species of _Daphne_.

Order 2. =Elæagnaceæ.= Shrubs or trees, which are easily recognised by the covering of _peltate hairs_ found upon almost all parts of the plant, causing them to assume a _silvery_ or rusty-brown appearance. Stipules are absent; the leaves are simple, most frequently scattered. Flowers (Figs. 484, 485) frequently unisexual. The sepals are valvate, 2-4; the _corolla is wanting_; _stamens_ 4 + 4 or 0 + 4. The ovule is _erect_ and _the radicle turned downwards_ (Fig. 486). The fruit is a _nut_, but becomes _a false fruit_, being surrounded by the persistent receptacle or the lower part of it, and thus assuming a berry- or drupe-like appearance (Fig. 486). Endosperm insignificant.--_Shepherdia_ (opposite leaves) has 4 sepals, 4+4 stamens, as in _Daphne_. Diœcious.--_Elæagnus_ (Silver-leaf) is ☿, has 4–6 sepals, and 4–6 stamens alternating with them. _Hippophaë_ is diœcious; it has 2 sepals and 4 stamens in the ♂-flower (perhaps properly speaking 2+2 stamens); thorny (stem-structures).

16 species; especially ornamental shrubs, _e.g. Elæagnus argentea_, _angustifolia_; _Hippophaë rhamnoides_ and _Shepherdia canadensis_. Northern Temp.

Order 3 (?). =Proteaceæ.= This order has its chief centre in the dry regions of Australia (6/10–7/10 of about 1,000 species), a smaller number in S. Africa (2/10–3/10). a few species in S. Am. Trees or shrubs, leaves generally scattered, without stipules, and more or less dry, leathery, evergreen, and often of very different forms on the same plant (undivided, compound, etc.) The flowers are ☿ (rarely unisexual), and _4-merous_ in the single, petaloid perianth and in the staminal whorl; 1 carpel; sometimes zygomorphic. The perianth-leaves are generally almost free, with _valvate_, æstivation, often leathery. Small scales alternating with the perianth are often found at the base of the ovary. The stamens generally have extremely short filaments, and are situated opposite, sometimes quite on the tip of the perianth-leaves, in a spoon-like groove. The gynœceum is 1-locular, has 1–several ovules, and is often raised on a stalk-like internode. The fruit is a follicle or nut. The seeds, most frequently winged, have no endosperm.--_Protea_, _Manglesia_, _Hakea_, _Banksia_, _Grevillea_, etc. 50 genera; about 1,000 species. Several species are cultivated in our conservatories for the sake of the flowers, which are beautifully coloured and arranged in crowded inflorescences. Protandrous. It is doubtful whether they were existent in Europe in the Tertiary Period. The true systematic position of the order is doubtful. They are related to the Leguminosæ and Rosifloræ, but more closely no doubt to the two preceding orders.

Family 19. =Saxifraginæ.=

The flower is generally perfect, regular and polypetalous, usually _perigynous_ or _epigynous_, _eucyclic_ and 5-merous; most frequently S5, P5, A5 + 5 or 5 + 0 and G=2=-5, but other numbers are found, especially 4; the flowers are very frequently obdiplostemonous. The calyx is sometimes large and the corolla small; the carpels in some are entirely free, in others more or less united. Endosperm is found in the majority. ~The hypogynous forms approach the Cistifloræ, the others the following families, especially the Rosifloræ. This family is not, upon the whole, so well defined and natural as most of the others. The Saxifragaceæ proper, approach very near to the Rosaceæ, especially _Spiræa_, and form a transition to it. The forms with opposite leaves, as _Philadelphus_, etc., approach the Myrtifloræ, just as the Escalloniæ appear to be closely allied to Bicornes, especially _Vacciniaceæ_. Finally through _Pittosporaceæ_, they pass over to the Frangulinæ. The family terminates in very reduced forms, on the one hand in the arborescent orders with crowded inflorescences, on the other perhaps in the very remarkable order _Podostemaceæ_.~

Order 1. =Crassulaceæ.= Nearly all are herbs or small shrubs with round, succulent branches and scattered, _fleshy_, often more or less round leaves, which are very rarely incised, and never have stipules. The flowers are generally borne in dichasia or unipared scorpioid cymes, which again may be arranged in racemes, umbels, etc.; they are regular, ☿, hypogynous or perigynous, and most frequently have free sepals and petals (gamopetalous corollas with sessile stamens are found in _Cotyledon_, _Bryophyllum_, _Echeveria_, and others); the floral formula is Sn, Pn, An + n, Gn, where n may have very different values, partly depending upon the size of the flower (_e.g._ 4–7 in _Sedum_, Fig. 487; 6–30 in _Sempervivum_; 4 in _Rhodiola_, _Bryophyllum_, and _Kalanchoë_; 5 in _Echeveria_, _Umbilicus_, _Cotyledon_). The carpels are _free_ and are _placed opposite the petals_ (Fig. 487). Fruit a _syncarp composed of follicles_ containing many, small seeds without endosperm. Outside each carpel is found a small, nectariferous scale (Fig. 487). ~The northern genus, _Rhodiola_, is diœcious. The petal-stamens are wanting in some (_Crassula_, _Bulliarda_, and others). The floral-leaves are very often displaced upon their axillary branches. A multicarpellary gynœceum also occurs.~

_Sedum_ (Stonecrop) is generally 5-merous with 10 stamens; _Sempervivum tectorum_ (House-leek), 12-merous, and with 24 stamens. ~The leaves of _Bryophyllum calycinum_ very readily form buds, and also frequently exude water from the edges.~

485 species; especially Temp. (Cape, Europe). Principally used as ornamental plants.

Order 2. =Saxifragaceæ.= The flowers are 4–5-merous with =2= (-3) carpels, most frequently: S5, P5, A5 + 5 (obdiplostemonous), G2. They are regular, ☿, polypetalous, hypogynous, perigynous or most frequently _more or less epigynous_ (Fig. 488). The carpels may be individually quite free, but are more frequently united at the base, or the entire portion enclosing the ovules is united into a 1- or 2-locular ovary, the styles, however, are always free. _Fruit a capsule_ with many seeds; endosperm present.--They are herbs, most frequently with _scattered_ leaves without stipules; but the leaf-base is broad. The inflorescences are most frequently cymose, and a displacement of the floral-leaves is frequent (_e.g._ _Chrysosplenium_).--~Some _Saxifraga_-species, _e.g._ _S. sarmentosa_, have irregular flower with an _oblique_ plane of symmetry. The petal-stamens in some may be wanting: _Heuchera_, species of _Saxifraga_ and _Mitella_. The corolla is wanting in others.~

_Saxifraga_ (Saxifrage): S5, P5, A5 + 5, G2 (Fig. 488); capsule bilocular, opening along the ventral suture between the 2 persistent styles. ~_S. granulata_ has small tubers at the base of the stem.~--_Chrysosplenium_ (Golden Saxifrage): 4 sepals, _no corolla_, 4 + 4 stamens; 1-locular capsule.

Protandry is most frequently found in _Saxifraga_, with the stamens successively bending towards the gynœceum; protogyny is more rare. In other genera there is protogyny without any movement of the stamens; _Chrysosplenium_ is homogamous.--About 300 species; mostly in temperate climates. _Saxifraga_ is especially Alpine. _S. crassifolia_ and other species, _Hoteia japonica_, _Tellima_, etc., are ornamental plants.

The following genera are allied to the Saxifragaceæ:--