The families of flowering plants

L. Watson and M.J. Dallwitz

Molluginaceae Hutchinson

~ Aizoaceae.

Including Adenogrammataceae Nak., Limeaceae Shipunov ex Reveal, Polypodaceae Nak.

Habit and leaf form. Herbs, or shrubs (or subshrubs). Plants non-succulent. Annual to perennial. Mesophytic, or xerophytic (?). Leaves alternate, or whorled; non-sheathing; simple; epulvinate. Lamina entire. Leaves stipulate, or exstipulate. Stipules caducous, or persistent. Leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial, or centric. Stomata present; anomocytic.

Axial (stem, wood) anatomy. Nodes unilacunar. Internal phloem absent. Secondary thickening anomalous. The anomalous secondary thickening via concentric cambia.

The vessel end-walls simple. ‘Included’ phloem absent.

Reproductive type, pollination. Plants hermaphrodite (usually), or monoecious.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in cymes. The ultimate inflorescence units cymose. Flowers small; regular; cyclic. Free hypanthium absent. Hypogynous disk present, or absent; when present, annular.

Perianth with distinct calyx and corolla, or sepaline (the petals small or absent); 4–10; 1 whorled, or 2 whorled. Calyx 5 (usually), or 4 (Polpoda); 1 whorled; polysepalous (usually), or gamosepalous (basally joined in Coelanthum). Calyx lobes markedly longer than the tube. Calyx regular; persistent; imbricate. Corolla when present, 5 (small); 1 whorled; polypetalous (usually), or gamopetalous (connate below into a tube in Orygia and Corbichonia); regular.

Androecium (2–)5–10(–25). Androecial members branched, or unbranched; free of the perianth; free of one another, or coherent (at the base of the filaments); 1 adelphous, or 5 adelphous (?); 1 whorled, or 2 whorled. Stamens (2–)5–10(–25); reduced in number relative to the adjacent perianth, or isomerous with the perianth, or diplostemonous to polystemonous. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall of the ‘monocot’ type. Pollen grains aperturate; 3 aperturate; colpate; spinulose; 3-celled.

Gynoecium (1–)2–5(–10) carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth, or increased in number relative to the perianth. The pistil 2–5 celled. Gynoecium monomerous (Adenogramma), or syncarpous; of one carpel (Adenogramma), or synovarious, or synstylovarious (Glinus); superior. Carpel in Adenogramma fully closed; apically stigmatic; 1–12 ovuled (?). Ovary plurilocular; 2–5 locular. Gynoecium stylate. Styles 1, or 3–5; free; apical. Stigmas papillate. Placentation axile. Ovules 1–25 per locule (?); arillate, or non-arillate; campylotropous (usually), or hemianatropous (almost); bitegmic; crassinucellate. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral, or persistent (Limeum). Endosperm formation nuclear.

Fruit non-fleshy; dehiscent (usually), or indehiscent; usually a capsule. Capsules loculicidal (or by transverse slits). Seeds non-endospermic. Perisperm present. Seeds with starch. Embryo well differentiated. Cotyledons 2. Embryo achlorophyllous (1/1); curved. The radicle dorsal.

Physiology, phytochemistry. C3, or C3-C4 intermediate. C3 physiology recorded directly in Glinus, Limeum, Mollugo, Orygia. C3-C4 intermediacy in Mullugo nudicaulis, M. verticillata. Anatomy C4 type (Glinus, Mollugo, Trianthema), or non-C4 type (Glinus, Limeum, Mollugo, Pharnaceum). Cyanogenic, or not cyanogenic. Betalains absent. Saponins/sapogenins present, or absent. Aluminium accumulation not found. Sieve-tube plastids P-type; type III (a).

Geography, cytology. Holarctic, Paleotropical, Neotropical, and Cape. Temperate to tropical. Mainly tropical and subtropical. X = 9.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Caryophylliflorae; Caryophyllales. Cronquist’s Subclass Caryophyllidae; Caryophyllales. APG 3 core angiosperms; core eudicot; Superorder Caryophyllanae; Order Caryophyllales.

Species about 100. Genera 15; Adenogramma, Coelanthum, Corbichonia, Corrigiola, Glinus, Glischrothamnus, Hypertelis, Limeum, Macarthuria, Mollugo, Pharnaceum, Polpoda, Psammotropha, Suessenguthiella, Telephium.

General remarks. Apart from absence of betalains and differences in photosynthetic pathways (with data for both reflecting limited sampling), Molluginaceae seem to differ from the more variable Aizoaceae sensu stricto (q.v.) only in being non-succulent.

Illustrations. • Le Maout and Decaisne: Telephium. • Pharnaceum acidum: Hook. Ic. Pl. 11 (1867–71). • Corbichonia decumbens, as Glinus trianthemoides: R. Wight (1850). • Glinus lotoides: Hutchinson. • A foliar hair of Glinus, with leaf sections of Aizoon and Mesembryanthemum (Aizoaceae): Solereder, 1908..

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or 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). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 24th October 2017.’.