850 Appendix 



Phenotype (fe' no tipe) (Gr. phaino, show; typos, impression), a type or kind 

 determined on the basis of visible traits as distinguished from genotype 

 (based on gene content). 



Phloem (flo' em) (Gr. phloios, bark), food-conducting tissue of plants; phloem 

 and xylem together form a vascular bundle. 



Photosynthesis (fo to -sin' the sis) (Gr. phos, Hght; synthesis, to build), produc- 

 tion of carbohydrates from water and carbon dioxide by means of chloro- 

 phyll in presence of light (to supply energy). 



Phototaxis (fo to -tax' is) (Gr. phos, light; taxis, response), response to light. 



Phototropism (fo -tot' ro pizm), see Phototaxis. 



Phrenic (fren' ik) (Gr. phren, diaphragm), pertaining to the diaphragm. 



Phycocyanin (fy co -si' a nin) (Gr. phycos, seaweed or alga; kyanos, blue), blue 

 pigment of the blue-green algae. 



Phycoerythrin (fy co e -ryth' rin) (Gr. phycos, alga; erythros, red), red pigment 

 of red algae. 



Phycomycetes (fi co mi -se' tez) (Gr. phycos, alga; mycetes, fungi), filamentous 

 (algalike) fungi. 



Phylogeny (filoj'eni) (Gr. phylon, race; gen, descent), ancestral history of a 

 race or group as contrasted with ontogeny. 



Phylum (fi' lum) (Gr. phylon, tribe), one of the main groups into which the ani- 

 mal and plant kingdoms are divided (plural, phyla). 



Physiology (fizi-ol'oji) (Gr. phusis, nature; logos, study), study of functions. 



Phytogeography (fi to ge -og' ra fi) (Gr. phytos, plant), geographic distribution 

 of plants ; same as Plant geography. 



Phytopathology (fi to pa thol' o ji) (Gr. phyto, plant; pathos, diseased), study of 

 diseased or abnormal plants. 



Pia mater (pi' a; ma' ter), inner of three coverings of brain and spinal cord. 



Pigmentation of plants, various colors of plants produced by such specific pig- 

 ments as chlorophyll, xanthophyll, carotene, anthocyanins, and flavones of 

 higher plants and phycoerythrin, phycocyanin, fucoxanthin in algae, etc. 



Pineal (pin'eal) (L. pinea, cone), small endocrine gland between the two cere- 

 bral hemispheres. 



Pisces (pis' es) (L. piscis, fish), class of vertebrates to which fishes belong. 



Pistil (pis' til) (L. pistilum, a pestle), the ovule-producing part of a flower, con- 

 sisting of one or more carpels. 



Pith (A.S. pitha, pith), soft, spongy tissue in the center of the stems of certain 

 plants. 



Pituitary (pi -tu' i ta ri) (L. pituita, phlegm), small, oval endocrine gland attached 

 to the infundibulum of the brain whose two lobes have entirely different 

 hormones." 



Placenta (pla -sen' ta) (Gr. plakous, flat cake), flat vascular organ which aids in 

 nourishing the fetus in the uterus; or attachment of plant seeds. 



Plankton (plangk' ton) (Gr. planktos, wandering), animal and plant life floating 

 in the water. 



Plant geography, see Phytogeography. 



Plasma (plaz'ma) (Gr. plasma, liquid), liquid part of the blood, lymph, or milk. 



Plasmagene (plaz'majen) (Gr. plasma, form; genos, descent), a gene within 

 the cytoplasm in contrast to a nuclear gene; sometimes called a cytogene. 



