Fig. 486.—Longitudinal section through the fruit.
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 G2-5, 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.
Fig. 487.—Diagram of a 6-merous flower (Sedum hispanicum): w branch of scorpioid cyme in the axil of the bracteole β.
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.