The families of flowering plants
The families of flowering plants | |
~ Orchidaceae
Including Neuwiediaceae (Burns-Balogh & Funk) R. Dahlgren ex Reveal & Hoogland
Habit and leaf form. Leaves simple. Lamina entire; lanceolate; parallel-veined; without cross-venules. Vernation plicate.
General anatomy. Plants with silica bodies (these in idioblasts (stegmata) occurring along the fibres surrounding the vascular bundles).
Leaf anatomy. Epidermis without silica bodies. Stomata present; tetracytic, or anomocytic and tetracytic. Hairs absent.
The mesophyll containing calcium oxalate crystals. The mesophyll crystals raphides. Vessels absent.
Stem anatomy. Primary vascular tissue in scattered bundles; centrifugal. Secondary thickening absent. Xylem without vessels.
Root anatomy. Roots with velamen. Root xylem with vessels; vessel end-walls scalariform and simple (mainly simple).
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’. The ultimate inflorescence unit racemose. Inflorescences scapiflorous; racemes, sometimes branched; espatheate. Flowers somewhat irregular to very irregular; more or less zygomorphic; resupinate (Neuwiedia), or not resupinate (Apostasia). The floral irregularity involving the perianth and involving the androecium (more consistently the latter). Flowers 3 merous; cyclic; supposedly basically pentacyclic. Perigone tube absent.
Perianth of ‘tepals’; 6 (3+3); free; 2 whorled (the median inner member sometimes larger, forming a labellum); isomerous; petaloid; white, or yellow.
Androecium 2–3 (the median of the outer whorl, which is sometimes missing, and the two laterals of the inner whorl). Androecial members free of the perianth; partially united with the gynoecium; coherent (at the base, and with the style); theoretically 2 whorled, or 1 whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1 (the median member); external to the fertile stamens. Stamens 2, or 3; isomerous with the perianth; alterniperianthial (when the median of the outer whorl is present), or oppositiperianthial (when only the two laterals of the inner whorl are present); filantherous to with sessile anthers. Anthers dorsifixed to basifixed; dehiscing via longitudinal slits; introrse. The endothecial thickenings spiral. Microsporogenesis simultaneous. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate (operculate).
Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary 3 locular. The ‘odd’ carpel anterior. Styles 1. Stigmas 1; 2–3 lobed; capitate. Placentation axile. Ovules 10–50 per locule (i.e. ‘many’); anatropous.
Fruit fleshy, or non-fleshy; indehiscent (disintegrating, usually), or dehiscent; a capsule. Capsules when dehiscent, loculicidal (Neuwiedia). Fruit 30–100 seeded (‘many’). Seeds minute. Embryo rudimentary at the time of seed release, or weakly differentiated. Testa without phytomelan; hyaline.
Seedling. Seedling collar not conspicuous. Coleoptile absent. Primary root ephemeral.
Geography, cytology. Tropical. S.E. Asia, Indomalaya, tropical Australia.
Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Orchidales. APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Asparagales (as a synonym of Orchidaceae).
Species 20. Genera 3; Apostasia, Adactylus, Neuwiedia.
Illustrations. • Technical details (Lindley). • Floral diagrams (Apostasia, Neuwiedia).
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. 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: 19th December 2012. http://delta-intkey.com’.
