Phylum 



OF BOTANICAL TERMS. 



Pilus 



trace the origin of species, va- 

 rieties, etc., aud their various 

 organs from preexisting forms. 

 It deals with the history of a 

 species or other group, in dis- 

 tinction from Ontogeny, which 

 deals with the history of an in- 

 dividual. See Evolution,. 



PHYLUM (pi. Fhy'la), a scale, 

 group, or system of organisms 

 arranged in the manner in 

 which its individuals or subor- 

 dinate groups have succeeded 

 each other in point of time. 



PHYSIOLOGICAL BOTANY, the 

 science which treats of how 

 plants live, grow, and per- 

 form their various functions; 

 vegetable physiology. 



PHYTOGEN'ESlS, plant reproduc- 

 tion, germination, and devel- 

 opment, or the science which 

 treats of these processes; phy- 

 togeny. 



PHYTOG'ENY, see Phytogene- 



SIS. 



PHYTOGEOG'RApHY, see Geo- 

 graphical Botany. 



PHYT6G'RAPHY, descriptive bot- 

 any, including both the de- 

 scribing and naming of plants. 

 See Vegetable Taxonomy. 



PHY'TOID, plant-like. 



PHY'TOLITE, see Phytolith. 



PHY'TOLITH, a fossil petrified 

 plant; phytolite. 



PHYt6LITH6L'OGY, see Fossil 

 Botany. 



PHYtOL'OGY, see Botany. 



PHYTOL'YSIS, the change in 

 position uudergone by the 

 chlorophyll of a cell in con- 

 sequence of the alternation of 

 day and night or of the in- 

 tensity of the sunlight. See 

 Apostrophe, Epistrophe, 

 and Systrophe. 



PHY'TOMER, see Phyton. 



PHY'TON, an internode with a 

 node at its upper extremity 

 which bears one or more 

 leaves, in the axil of each of 

 which may appear one or 

 more buds; phytomer. The 

 name was given by Gaudi- 

 chaud, who regarded plants 

 as compound individuals 

 made up of successive pliytons. 

 See Metamer. 



PHYTON'OmY, see Physiolog- 

 ical Botany. 



PHYtCN'YMY, see Physiolog- 

 ical Botany. 



PHYTOPATHdL OGY, see Vege- 

 table Pathology. 



PHYTdT'OMY, (1) the science of 

 vegetable anatomy; (2) the 

 art or act of plant-dissection. 

 Compare Structural Bot- 

 any 



PHYT6z6'6N (pi. Phytozoa) 

 (obs.), see Antherozoid. 



PI'LEATE, like a pileus; having 

 a cap or pileus; pileiform. 



PILE'lFdRM, shaped like the 

 pileus or cap of a mushroom. 



PlLE'OLtTS (pi. PIle'611), a little 

 pileus, especially where there 

 are several from the same 

 stem. 



PILEORHl'ZA, see Boot-cap. 



PI'LOUS, see Pilose. 



PILEUS (pi. PI'lei), the cap of 

 mushrooms. Extended to 

 other similar objects, as the 

 stalked stroma of Claviceps. 



PILIF'EROUS, bearing hairs. 



PlL'IFdRM, hair-like. 



PILlG'EROUS, producing hairs. 



PILOSE', (1) covered with long, 

 soft, nearly erect and some- 

 what distant hairs; (2) having 

 the nature of hair. 



PI'LUS (pi. PI'lI), a hair. 



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