GLOSSARY 425 
which originates through the breaking down of cell walls common to a group 
of cells. 
Macro. A prefix of Greek origin meaning large. 
Macrosporan'gium. —A spore case containing one or more macrospores. (The 
nucellus in Spermatophytes.) 
Mac'rospores. —The larger of the two different kinds of spores produced by some 
of the higher Pteridophytes and the Spermatophytes. (The embryo-sac 
in Spermatophytes). 
Macrospo'rophyll. —The leaf bearing the macrosporangium. (The carpel in 
in Spermatophytes.) 
Mac'ulate. —Spotted. 
Ma'millate. —Bearing teat-like protuberances. 
Marces'cent. —Withering but not falling, dropping off. 
Marine'. —Applied to plants which grow in the sea or ocean. 
Medul'la. —Pith. 
Med'ullary. —Pertaining to the pith. 
Med'ullary Rays. —Strands of parenchyma connecting the cortex with the pith 
or a portion of the xylem with a portion of the phloem. 
Megasorus. —The ovule. 
Megasporan'gium. —See macrosporangium. 
Megaspore. —See macrospore. 
Mem'branous. —Thin, soft and flexile. 
Mer'icarp. —One of the two inferior akenes which are found with the carpophore 
making up the cremocarp in Umbelliferae. 
Mer'istem. —Formative tissue consisting of cells which in the living plant are 
in an active state of division. 
Meristemat'ic. —Consisting of generative cells or meristem. 
Mes'ocarp. —The middle layer of the fruit wall or pericarp. 
Mes'ophyll. —All of the leaf parenchyma within the epidermis. 
Mes'tome. —The conducting portion of a fibrovascular bundle. 
Metab'olism. —The sum total of all the chemical changes which take place in 
a living plant. 
Metagen'esis. —Alternation of generations. The production of sexual indi¬ 
viduals by asexual means and asexual or neutral individuals by sexual means. 
Metamor'phosis. —A change in the form or function of an organ or organism. 
Micro. —A prefix of Greek origin meaning small. 
Mi'crobe. —A minute vegetable or animal organism. 
Mi'cropyle. —The opening between the coats of an ov^e through which the pol¬ 
len tube enters. The orifice or foramen in the seed coat through which the 
hypocotyl passes during germination. 
Microso'mes. —Applied by Strasburger to minute particles in the protoplasm 
which have a high degree of refringency. 
Microso'rus. —A lobe of the anther. 
