Part 73

The majority of plants belonging to this family inhabit cold and temperate countries, or high mountains in tropical regions; they prefer cold and dry or damp places (bogs, heaths, etc.). Plentiful in N. America.

Order 1. =Pyrolaceæ.= Perennial herbs; petals most frequently quite free from each other, and falling off singly after flowering; the anthers are without appendages, and open by pores (Fig. 544), or by a transverse slit. The placentæ are thick. The seeds in the capsule-like fruit (loculicidal dehiscence) are exceedingly small and light, they have a sac-like testa which loosely envelops them, an oily endosperm, and an extremely simple embryo, which consists only of an ellipsoidal, cellular mass, without cotyledons or differentiation into plumule and radicle.

Pyrola (Winter-green) is green, and has also large evergreen foliage-leaves. The flowers, 5-merous, are most frequently borne in racemes without a terminal flower; the anthers are extrorse in the bud with the pores in the lower portion (Fig. 544 A), but they become inverted at a later period, so that the pores open at the top (Fig. 544 C). ~P. uniflora has a single, terminal flower; it winters by its roots, producing from these in the spring aerial, quite unbranched shoots. Chimaphila umbellata.~

Monotropa (Yellow Bird’s-nest) is very pale yellow, without chlorophyll, succulent, and has only scale-like leaves closely pressed upon the stem; it is a saprophyte. The raceme has a terminal flower, and is pendulous before flowering. The anthers open by a semicircular, transverse cleft. ~M. hypopitys reproduces chiefly by root-shoots.~

About 30 species, especially N. Europe, N. America, and N. Asia.

Order 2. =Ericaceæ.= The flower (Fig. 545) is hypogynous, the median sepal posterior; corolla, gamopetalous; the stamens are generally 2-horned, and the fruit is a capsule, less frequently a berry or drupe. At the base of the ovary is a nectar-secreting disc (Fig. 545 B). This order comprises shrubs or undershrubs (rarely small trees), which are evergreen, and as a rule have densely crowded leaves.

=1.= ERICEÆ, HEATH GROUP. Flowers most frequently 4-merous (S4, P4, A4 + 4, G4, united in a 4-locular gynœceum), rarely 5-merous. The withered corolla persists after flowering. The leaves are most frequently acicular, opposite or verticillate; the buds are without scales. The fruit is a capsule.--Calluna (C. vulgaris, Ling) has a deeply 4-cleft corolla, which is less than the coloured calyx; capsule with septicidal dehiscence.--Erica (about 420 species; E. tetralix, Cross-leaved Heath) has a tubular or bell-shaped, 4-dentate corolla, which is much longer than the calyx. Capsule with loculicidal dehiscence.--Pentapera.

=2.= ANDROMEDEÆ. The flowers are 5-merous (S5, P5, A5 + 5, G5), with deciduous corolla. Capsule with loculicidal dehiscence. The leaves are scattered, and incline more to the ordinary broad-leaved forms.--Andromeda; Gaultheria; Cassandra (Lyonia); Cassiope.

=3.= ARBUTEÆ. The flowers as in the preceding group (Fig. 545), but the fruit is a berry or drupe. Arctostaphylos (A. uva-ursi, Bear-berry) has a drupe with 5 stones in a dry, farinaceous pulp; in other species there is 1 stone with several loculi. Arbutus (A. unedo, Strawberry-tree) has a spherical berry.

Pollination is effected by means of insects, especially by bees. The pollen is light and dry, and is shaken out through the pores of the anthers when the insects agitate the horn-like appendages during their visits. Self-pollination takes place, no doubt, in many cases.--800 species; the very large genus, Erica, especially in S. Africa (the Cape).--OFFICINAL: the leaves of Arctostaphylos uva ursi. Arbutus unedo (S. Europe) has an edible, peculiarly warted (strawberry-like) fruit. Many Erica-species are cultivated as ornamental plants.

Order 3. =Rhodoraceæ= (=Rhododendrons=). This differs from the preceding order in the median sepal being anterior, and hence the position of the other floral whorls is also reversed. The flower is hypogynous, in most cases 5-merous; the corolla is most frequently deeply cleft or polypetalous, and falls off after flowering; the anthers open by pores, and have no horn-like appendages. Capsule with septicidal dehiscence.--The shrubs or small trees belonging to this order have, like the Vaccineæ, ordinary foliage-leaves, and the buds are generally provided with large bud-scales.

Rhododendron has 10 stamens, and a slightly zygomorphic flower with deeply 5-cleft corolla (the section Azalea has frequently only 5 stamens, the petal-stamens being absent). They are Alpine plants (200 species) in the mountains of Asia, especially the Himalayas; some in S. Europe.--Menziesia.--Ledum; small, rusty-brown, hairy shrubs with polypetalous, expanded, star-like corolla.--Kalmia (N. Am.) has a cupular corolla, with 10 small, pocket-like depressions in which the anthers are concealed until the arched, elastic filaments are freed from this position by means of the insects, when they quickly straighten themselves in the centre of the flower.--Phyllodoce; Loiseleuria (5 stamens); (Clethra (?); also placed among the Ternstrœmiaceæ).

About 270 species. Several species are ornamental plants. Several plants of the order are more or less narcotic. Ledum palustre has been used as a substitute for hops.

Order 4. =Diapensiaceæ.= Hypogynous flower. 3 floral-leaves beneath the flower (S5, P5, A5 + 0, G3). Stamens on the throat of the corolla. Pollen-grains single. Disc absent. Capsule loculicidal.--9 species from the Arctic regions. It is doubtful whether this order should be included in the Bicornes; perhaps it would be more correctly assigned to the Polemoniaceæ.

Order 5. =Epacridaceæ.= This order comprises those species of the family which are confined to Australia and the South Sea Islands. They are shrub-like plants, resembling the Ericaceæ in habit, in the inflorescence, and in the structure, form, and colour of the flower. They differ especially in having only 1 whorl of stamens (placed opposite the sepals) and in the anthers having only 2 loculi, and opening by a longitudinal slit. Fruit most frequently a drupe (or loculicidal capsule). Epacris-and Styphelia-species are ornamental plants. About 325 species.

Order 6. =Vacciniaceæ= (=Bilberries=). The flower (Fig. 546) is epigynous, the corolla gamopetalous, and the fruit a berry. The latter is most frequently spherical, and bears on its apex the calyx, which is generally very low, almost entire, and with a disc-like expansion inside. The flower is 4- or 5-merous (Fig. 546 B, D). The anthers have 2 pores, and are most frequently 2-horned (Fig. 546 F, G). Small shrubs; the leaves are scattered, not needle-like.

Vaccinium (Bilberry, Whortleberry) has an urceolate, gamopetalous, only slightly dentate corolla, and horn-like appendages to the anthers (Fig. 546). ~V. vitis idæa (Cowberry) is evergreen, with flowers in racemes, and bright red berries; V. myrtillus (Bilberry) and V. uliginosum (Bog Whortleberry) both have black berries with a blue bloom, leaves deciduous.~--Oxycoccus has a polypetalous corolla with the petals projecting backwards. Anthers without appendages. ~O. palustris (Cranberry) has a slender, creeping stem, and is evergreen. Dark red berry.~

Pollination essentially the same as the preceding order.--320 species; especially in N. Am. Some are useful on account of their edible fruits, especially Vaccinium myrtillus and V. vitis-idæa, and in a less degree Oxycoccus, etc. The fruits of V. myrtillus are officinal.

Family 27. =Diospyrinæ.=

The flowers are regular, gamopetalous, typically diplostemonous, with the same number throughout all 5 whorls, thus: Sn, Pn, An + n, Gn, where n most frequently =5 (4–6), rarely 3, 7 or 8. Of the two whorls of stamens the one opposite the sepals is often present only as rudiments or is entirely suppressed, and the completely developed stamens are thus placed opposite the petals. The carpels are generally placed opposite the sepals. The ovary is multilocular with the ovules attached in the inner angles. The fruit is most frequently a berry. The seeds are large, generally solitary, or a few in each loculus.--All plants belonging to this family are trees or shrubs with scattered, single, most frequently entire, penninerved and leathery leaves without stipules; the majority are tropical (America, Asia), some are found in N. Am. and the Mediterranean.

Order 1. =Sapotaceæ.= Plants with latex; anthers extrorse, 1 erect ovule in each loculus; fruit a berry; the seeds with bony, shiny brown testa have a large, lateral hilum. The leaves are frequently covered with silky hairs.--A useful order in several respects (400 tropical species). The wood of some genera, such as Sideroxylon (Iron wood) and Bumelia, is as hard as iron. The latex of Palaquium (P. oblongifolium, P. gutta, and other species), Mimusops and Payena (Sumatra, E. Ind.), is the raw material of gutta percha. The following have very delicious fruits: Lucuma mammosa, Achras sapota, Chrysophyllum cainito (Star-apple), etc. The seeds of Bassia (E. Ind.) contain a large quantity of a fatty oil. Isonandra, Mimusops schimperi are often found in the Egyptian royal tombs.

Order 2. =Ebenaceæ.= Plants without latex, often diœcious; flowers with a more or less leathery perianth. The number of stamens is sometimes increased (by splitting?); ovules 1–2, pendulous in each loculus. Fruit a berry.--250 species; chiefly tropical. Some are well known on account of their hard and black-coloured heart-wood, e.g. Maba ebenus (the Moluccas) and Diospyros ebenum (Ebony-wood, from Tropical Asia) and others.--The fruits are edible e.g. of Diospyros lotus (Date-plum, Asia), which is also cultivated as an ornamental shrub, together with several other species.

Order 3. =Styracaceæ.= The flower is more or less epigynous, and the corolla is almost polypetalous. The stamens (by splitting?) are more than double the number of the petals, and often united at the base. Stellate hairs are frequent.--235 species; Tropical Asia and America, a few for example in the East.--OFFICINAL: Gum-benzoin from Styrax benzoin and perhaps other species (Sumatra and Siam). Halesia tetraptera (N. Am.) is an ornamental shrub with 4-winged fruits.

Family 28. =Primulinæ.=

The flowers are regular, ☿, hypogynous, and gamopetalous. The stamens are equal in number to the petals (Fig. 547) and are placed opposite to them. The ovary is unilocular, with a free, central placenta with 1–many ovules.--The flower is a further development of the Diospyrinæ; the suppression of the calyx-stamens, which commenced in this family, is carried further in the Primulinæ, so that in the majority of cases no trace of them is present, but in certain species and genera (Samolus, Lysimachia thyrsiflora, Soldanella, certain Myrsineæ) some small bodies (scales, teeth, etc.) are found in the position of the suppressed stamens. Again, the lateral portions of the carpels are suppressed, so that the ventral placentæ with the ovules are separated from the dorsal portions, and are united into a free central placenta; this theory is supported by the branching of the vascular bundles, the development, and various comparative considerations.--Sn, Pn, A0 + n, Gn; where n = 4–8, generally 5. The carpels are placed opposite the sepals (Fig. 547).

Order 1. =Primulaceæ= (=Primroses=). This order has many ovules attached to a thick, free, central placenta (Fig. 547); style undivided with a capitate stigma; ovules semi-anatropous; fruit a capsule with many seeds.

All the plants belonging to this order are herbs; stipules wanting; the flower is most frequently 5-merous (S5, P5, A0 + 5, G5; except Centunculus and Trientalis). The corolla and capsule have various forms, but the capsule generally opens by teeth at the apex. The ovules are semi-anatropous (in Hottonia they are anatropous), and the seeds are therefore peltate, with the hilum situated in the centre of one side. The endosperm is fleshy or horny. The flowers are borne either in racemes or in umbels; as bracteoles are typically absent (Fig. 547), cymose branching does not occur.

Primula (Primrose) has most frequently a vertical rhizome, bearing a rosette of leaves at its summit, and long-stalked umbels; corolla rotate or slightly funnel-shaped; the capsule opens at the apex by 5 teeth. The flowers in some species are heterostyled (long-styled or short-styled; Fig. 548). Closely allied are Androsace (with ovate, cup-shaped corolla-tube and ligular scales, alternating with the corolla-lobes) and Soldanella (funnel-shaped corolla with laciniate lobes and most frequently ligular scales).--Hottonia (Water-Violet) is an aquatic plant with pectinate leaves and heterostyled flowers.--Cortusa. Dodecatheon. Cyclamen (Fig. 549) has solitary, long-stalked flowers, and a rotate corolla with the lobes reflexed; the stalk of the capsule rolls up spirally; the tuberous rhizome is formed by the hypocotyledonary internode. Only 1 cotyledon.--Lysimachia (Money-wort); stem-internodes well developed, leaves opposite or verticillate, calyx almost polysepalous, corolla deeply 5-partite (Fig. 550). The flowers are solitary or in racemes.--Anagallis (Pimpernel), leaves opposite, flowers solitary; the fruit a pyxidium (Fig. 551); similarly in Centunculus, which is 4-merous.--Trientalis, the flowers are most frequently 7-merous.--Glaux (Sea Milk-wort) is a creeping maritime plant with opposite leaves; flowers solitary in the leaf-axils, corolla absent, but with coloured calyx. ~The petals are usually developed later than the stamens in the Primulaceæ; but in this instance they are entirely suppressed.~--Samolus (Brookweed) differs from all the others in having an epigynous flower; barren sepal-stamens are also present. The bracts in the racemose inflorescences are displaced along the flower-stalks.