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The families of flowering plants

L. Watson and M. J. Dallwitz

Joinvilleaceae Tomlinson & A.C. Sm.

Habit and leaf form. Coarse, reedlike, unbranched, erect herbs (to 5 m tall). Perennial; without conspicuous aggregations of leaves; to 3–5 m high; rhizomatous (the rhizomes congested, sympodial). Leaves large (the lamina up to 1 m long); alternate; distichous; flat; sessile; sheathing. Leaf sheaths tubular; with free margins. Leaves simple. Lamina entire; linear, or lanceolate (grasslike, not cirrhose); palmately veined to parallel-veined (most of the veins entering the blade from the sheath, but a few originating from the base of the midrib). Leaves ligulate (and more or less auriculate). Lamina margins serrate. Leaf development probably ‘graminaceous’. Vernation plicate.

General anatomy. Plants with silica bodies (abundant throughout the plant, deposited in the epidermal walls and as silica bodies around the vascular bundles). Chlorenchyma without ‘peg cells’.

Leaf anatomy. Epidermis conspicuously differentiated into ‘long’ and ‘short’ cells (cf. Gramineae); containing silica bodies. Stomata present; paracytic. Guard-cells ‘grass type’. The mesophyll not containing mucilage cells; without crystals (? — no raphides). Foliar vessels present; with scalariform end-walls, or with reticulately perforated end-walls and with scalariform end-walls.

Axial (stem, wood) anatomy. Young stems with hollow internodes. Secondary thickening absent.

The vessel end-walls scalariform and simple (mostly simple).

Root anatomy. Root xylem with vessels; vessel end-walls scalariform and simple.

Reproductive type, pollination. Plants hermaphrodite. Floral nectaries absent (?). Pollination anemophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles; not in ‘spikelets’. Inflorescences terminal; much branched, terminal panicles. Flowers bracteate; fairly small; regular; 3 merous; cyclic; pentacyclic. Perigone tube present to absent (the perianth members free to basally connate). Hypogynous disk absent.

Perianth of ‘tepals’; 6; free to joined; 2 whorled; isomerous; sepaloid (bractlike); similar in the two whorls to different in the two whorls (chaffy, the outer members much larger); green, or cream; persistent.

Androecium 6. Androecial members free of the perianth; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 6; isomerous with the perianth. Anthers basifixed (sagittate); non-versatile; dehiscing via longitudinal slits; latrorse; tetrasporangiate. The endothecial thickenings girdling. Microsporogenesis successive. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; ulcerate. The ulcus without an operculum (or with a vestigial operculum represented by coarse granules or exine fragments); with an annulus. Interapertural exine scrobiculate. Interapertural interstitium columellate. Pollen grains 3-celled.

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 3 locular. Gynoecium non-stylate (with three more or less sessile stigmatic areas), or stylate. Styles when developed, 3; free to partially joined; apical; shorter than the ovary (persistent). Stigmas 3. Placentation axile to apical. Ovules 1 per locule; pendulous; orthotropous. Outer integument contributing to the micropyle. Antipodal cells formed; 3; not proliferating. Synergids non-haustorial. Endosperm formation nuclear. Embryogeny probably asterad.

Fruit fleshy; indehiscent; a drupe (red, yellow or black). The drupes with one stone (with 1–3 seeds). Fruit 1–3 seeded. Seeds copiously endospermic. Endosperm mealy, starchy. Seeds with starch. Embryo rudimentary at the time of seed release, or weakly differentiated (undifferentiated, minute, discoid). Testa without phytomelan; thin.

Geography, cytology. Paleotropical. Tropical. Western Malaysia, Pacific. X = 18.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Commeliniflorae; Poales. APG 3 core angiosperms; Superorder Lilianae; commelinid Monocot; Order Poales.

Species 2. Genera 1; only genus, Joinvillea.

General remarks. See Tomlinson and Smith 1970, Campbell and Kellogg 1987.

Illustrations. • Joinvillea plicata, with Flagellaria: Nat. Pflanzenfam. II (1895). • Joinvillea ascendens: photo (Scott Zona).

The descriptions are offered for casual browsing only. We strongly advise against extracting comparative information from them. This is much more easily achieved using the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG).

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 22nd August 2016.’.