i8o GLOSSARY. 



Microsporc (small spore). The smaller spore of the two kinds 

 produced by certain Pteridophytes and all Spermatophytes. 



Microsporophyll (small spore-leaf). The leaf upon which the 

 microsporangium is borne. 



Midrib. The central or main rib of a leaf or thallus. 



Monoecious (one household) . Applied to those plants upon one of 

 which both kinds of gametes are borne. Strictly speaking, 

 the term applies only to the gametophyte stage of plants. 



Monopodial (having one foot). Said of a stem consisting of a 

 single and contimious axis (footstalk). 



Mutualism. A symbiotic relationship where the organisms are 

 mutually helpful. 



Mother-cell. A cell that produces new cells (usually) by internal 

 division. 



Mycelium (Fungus growth). The filamentous vegetative growth 

 of Fungi, composed of hyphac. 



Naked. "Wanting some usual covering. 



Nectary. The place or appendage in which nectar is secreted. 



Nerve. A simple vein or rib. 



Node (a joint) . That part of a stem which normally bears leaves. 



Nucellus (a little kernel). The mass of the ovule within the 

 integuments. 



Nucleolus (diminutive of nucleus) . The sharply defined rounded 

 part often seen in the nucleus. 



Nucleus (a kernel). The usually roundish mass found in the 

 protoplasm of most active cells, and differing from the 

 rest of the protoplasm in its greater density. 



Oogonium, pi. oogonia (egg-offspring). The female organ of 

 Thallophytes. 



Oophyta (egg-plants). A primary division of plants, named 

 from the mode of reproduction, the egg-spore plants. 



Oophyte is the English equivalent of Oophyta. 



Oosphere (egg-sphere). The female egg-cell; the mass of 

 protoplasm prepared for fertilization. 



Oospore (egg-spore). The egg-cell after fertilization. 



Open bundle. A fibro- vascular bur die which contains cambium. 



Operculum, pi. opercula (a cover or lid). In mosses the ter- 

 minal lid of the capsule. 



Ovary (egg-keeper). That part of the carpel which contains 

 the ovules. 



Ovule (an egg). The body which becomes a seed after fertili- 

 zation and maturation. 



