440 
THE SEAWEEDS 
Matrix. — (1) The body on which a plant grows. (2) The material in which cells or 
tissues are embedded. 
Meatus.— An intercellular passage. 
Medulla . — The central, usually looser, tissue of the thallus. 
Mohiliform . — Resembling a string of beads. 
Monochromatic. — Consisting of one colour. 
Monoecious . — Having the male and female reproductive organs separate but on the same 
individual. 
Monopodial. — Having a single and continuous axis. 
Monosiplionous . — Consisting of a single central siphon surrounded by jacket cells. 
Monosporangia . — Undivided tetrasporangia. 
Monostromati-c . — Composed of a single layer of cells. 
Mucronate . — Possessing a short and straight point. 
Multiaxial . — Thallus formed from numerous longitudinal filaments. 
Multifid . — Cleft into many lobes or segments. 
Muricate . — Rough, with short and hard tubercular excrescences. 
N emathecmm . — A wart-like elevation of the surface in some Rhodophyceae, containing 
antheridia and paraphyses or cystocarps. 
Nidulate. — Partially encased or lying free in a cavity. 
Node . — That part of a stem which normally bears a leaf or whorl of leaves. 
Nodose. — Having numerous or conspicuous nodes; knotty or knobly. 
Nucleus . — The central body of the cell which carries the hereditary factors, or chromo- 
somes. 
Oh conical. — Conical, but attached at the. narrower end. 
Oh cor date. — Inversely heart-shaped, the notch being apical. 
Ohovate . — Inversely ovate, with the distal end the broader. 
Ocellated . — Marked with circular spots of colour. 
Oohlast . — Filaments produced from the fertilized egg. 
Oogamous . — When the two gametes are differentiated into egg and sperm. 
Orifice. — A mouth or aperture; an opening. 
Ostiole . — The opening of the conceptacle or cystocarp. 
Paniculate . — When branches or inflorescence are in a loose pyramidal form. 
Paraphysis . — Sterile filaments occurring in the fructifications of algae and other low 
groups of plants. 
Parenchyma . — The soft cellular basal tissue of plants. 
Parietal . — Borne on, or belonging to the wall. 
Patent. — Spreading. 
Pectinated . — Pinnatifid with narrow segments set close like the teeth of a comb. 
Pedicellate . — Borne on a stalk. 
Pellucid . — Wholly or partially transparent. 
Peltate . — Shield-shaped, having the stem attached to the lower surface instead of the 
base or margin. 
Penicillate . — Pencil-shaped, with a tuft of hairs. 
Penninerved . — Pinnately veined. 
Penultimate . — Last but one. 
Percurrent . — Extending throughout the entire length. 
Pericarp. — The wall of a fruit, capsule or ovary. 
Pericentral .' — Around the centre. 
Periderm. — The outer layer of bark. 
Petiole . — The stalk between the leaf blade and the stem. 
Phyllodium. — A petiole or branch developed into the form of a blade. 
Phylogeny . — Ancestral history deduced from development. 
Piliferous . — Bearing hairs, or tipped with them; hair pointed. 
Pilose. — Hairy, usually with soft and distinct hairs. 
Pinna . — One of the primary divisions of a compound leaf. 
Pinnate. — With leaflets arranged along each side of a common petiole. 
Pinnule. — Secondary pinna. 
Placenta . — The tissue from which the sporangia arise. 
