Z Chromosome - Sometimes used for the Y chromosome, if the female is in the heterogametic sex.

Zeatin - A growth promoting substance which was first isolated from maize kernels. A derivative of adenine. {6-(4-Hydroxy- 3-methyl but - 2 - enyl) amino purine}.

Zygophore - A mycelial branch which is bearing a gametangium.

Zygosporophore - Thick - walled resting spore which is a product of sexual reproduction by fusion of contents of two similar gametangia; occurs in a group of phycomycete fungi, Zygomycetes, and in an order of green algae, Conjugales. Also employed for product of fusion of motile isogametes, e. g., in Chlamydomonas.

Zoid - Zoospore.

Zoidiophilous - Pollinated by animals.

Zonal Soil. A broad grout of soil which is found in one of the main climatic regions of the world.

Zoogloea - A mucilaginous mass of bacteria which are embedded in a slimy materiel derived from the swollen cell-walls.

Zoogonium = Zoospore.

Zoophily - When pollinat by animals.

Zoosporangium. A sporangium producing zoospores; present in certain fungi and algae.

Zonation - (1)) The formation of bands of different colour on the surface of a plant.
(2) The formation, by fungi in culture, of a concentric band of colour, texture, abundance of spores etc.
(3) The distribution of vegetation in bands, each is having its characteristic dominant species.

(4) A stage in the development of an oogonium in which the contents have been arranged in two or more well-marked zones.

Zone - A band of colour, hairs etc., which are on the surface.