Family Ruscaceae

Ruscaceae Spreng.

~ Former Liliaceae, Asparagaceae-Nolinoideae in APG III

Including Phlebaceae Dulac (p.p.)

Habit and leaf form. Shrubs (or subshrubs, often thicket forming), or lianas. Switch-plants; with the principal photosynthesizing function transferred to stems (in the form of glabrous, ovate to lanceolate, alternate, opposite or whorled, pointed phylloclades). Leaves much reduced (to scales). Self supporting, or climbing. Leaves minute; alternate, or opposite, or whorled; membranous.

Leaf anatomy. Stomata anomocytic. Guard-cells not ‘grass type’.

The mesophyll containing mucilage cells, or not containing mucilage cells (? — the leaves being reduced, but mucilage cells with raphides common throughout the plants); containing calcium oxalate crystals (?), or without calcium oxalate crystals. The mesophyll crystals if present in the reduced leaves, raphides (there being raphide cells throughout the plants). Minor leaf veins without phloem transfer cells (Ruscus).

Stem anatomy. Secondary thickening absent. Xylem with vessels, or without vessels. Vessel end-walls scalariform.

Root anatomy. Roots with velamen (known in Semele), or without velamen. Root xylem with vessels; vessel end-walls scalariform, or simple.

Reproductive type, pollination. Plants hermaphrodite, or monoecious, or andromonoecious (rarely), or dioecious, or polygamomonoecious. Gynoecium of male flowers pistillodial, or vestigial, or absent.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’. Inflorescences in racemelike clusters on the surfaces of the phylloclades (Ruscus), umbel-like clusters on their edges (Semele), or in terminal racemes separate from them (Danaë); racemes, racemelike or umbel-like. Flowers small (inconspicuous, articulated on their pedicels); regular; 3 merous; cyclic. Perigone tube present (urceolate, in Danaë), or absent. Hypogynous disk absent.

Perianth of ‘tepals’; 6; free, or joined; 2 whorled; isomerous; sepaloid, or petaloid; more or less similar in the two whorls, or different in the two whorls (the inner members sometimes narrower); green, or white, or cream; fleshy (sometimes with a fleshy corona), or non-fleshy.

Androecium 3, or 6. Androecial members free of the perianth; coherent (the filaments joined to form a short tube or column); 1 whorled, or 2 whorled. Androecium exclusively of fertile stamens. Stamens 3, or 6; isomerous with the perianth; oppositiperianthial (when 3), or alterniperianthial. Anthers sessile; dehiscing via longitudinal slits; extrorse; tetrasporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Microsporogenesis successive. The initial microspore tetrads isobilateral. Tapetum glandular. Pollen shed as single grains. Pollen grains nonaperturate (at least in some species); 2-celled (in Danaë and Ruscus).

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 1 celled, or 3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 1 locular, or 3 locular; sessile. Gynoecium shortly stylate. Styles 1; apical. Stylar canal present. Stigmas 1; wet type; papillate; Group III type. Placentation basal; axile. Ovules in the single cavity 2; 2 per locule; collateral; orthotropous, or hemianatropous; bitegmic; tenuinucellate. Embryo-sac development Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; proliferating (to form 5 cells), or not proliferating; ephemeral. Synergids hooked (with filiform apparatus).

Fruit fleshy; indehiscent; a berry (red); 1–4 seeded. Seeds endospermic. Embryo well differentiated. Cotyledons 1. Embryo achlorophyllous (2/3); straight (cylindrical, short). Testa without phytomelan; pale.

Seedling. Hypocotyl internode present (short). Seedling collar not conspicuous. Coleoptile absent. Seedling cataphylls present. Primary root persistent.

Physiology, biochemistry. Not cyanogenic. Alkaloids absent (?). Arthroquinones detected (Ruscus); polyacetate derived. Proanthocyanidins absent. Flavonols present (Danaë), or absent (Ruscus, Semele); in Danaë, kaempferol and quercetin. Ellagic acid absent. Saponins/sapogenins present (steroidal).

Geography, cytology. Holarctic, Paleotropical, and Cape. Temperate. Western and Central Europe, Mediterranean.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Asparagales. APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Asparagales (as a synonym of Asparagaceae).

Species 9. Genera 3; Ruscus, Semele, Danaë.

Illustrations.
• Technical details: Ruscus aculeatus.
• Ruscus aculeatus (B. Ent.).