Phaeocyst 



OF BOTANICAL TERMS. 



Phototonic 



PH.3£N6G'AMOtJS, see Phenoga- 



MOUS. 



PHEN6L6G'IcAL, see Pheno- 



LOGICAL. 



PH-K'OgYST, an old term for 



Nucleus. 



PHA'LAnX (pi. Phalange?), a 

 bundle of more or less cohe- 

 rent stameus with broad fila- 

 ments, as in some Malvaceae. 

 Compare Adelphia. 



PHANEROGAM, see Phenogam. 



PHANEROGA'MlAN.seePHENOG- 



AMOUS. 



PHANEROGAMIC, see Phenog- 



amous. 

 PHANER6G'AM0tJS, see Phenog- 



AMOUS. 



PHEL LEM, cork. 



PHEL'LODERM, green cells be- 

 neath the cork formed from 

 the inner layers of the phel- 

 logen; cork-cortex. 



PHEL'L6G£N, the inner active 

 growing layers of cork-tissue; 

 cork-cambium; cork-meristem. 



PHE'NOGAM, a flowering plant, 

 i.e., one which produces true 

 seeds; phanerogam. Compare 

 Cryptogam. 



PHENOGA'MIAN, see Phenog- 



AMOTJS. 



PHflNOGAM'tC, see Phenog- 



AMOU8. 



PHEN6G AMOtfS, producing true 

 flowers and seeds. Compare 

 Cryptogamous. 



PHENOL06ICAL, applied to the 

 blossoming of plants, and other 

 periodical phenomena of plants 

 and animals; phoenological. 



PHLO EM, that portion of a fibro- 

 vascular bundle which contains 

 the bast and sieve tissue; lep- 

 tome. In exogeus it is always 

 sharply defined from the re- 

 maining portion (xylem) by a 

 layer of cambium. The inner 



bark is derived from the phloem, 

 and the wood from the xylem. 



PHLO'flM-RAY, a ray or plate of 

 phloem between two medullary 

 rays. It is an outward con- 

 tinuation of a xylem-ray. 



PHLO'EM-SHEATH, a layer of 

 thin-walled cells surrounding 

 the fibrovascular cylinder next 

 within the cortex — usually 

 better defined in roots than 

 in stems; bnst-sheath; peri- 

 phloem; pericambium; vascu- 

 lar bundle-sheath. 



PHORAN'THlu*M, see Antho- 



DIUM. 



PHOTO - EP'iNASTY , downward 

 curvature due to the presence 

 of light. Compare Photo- 



HYPONA8TY. 



PHOTO - HY'PONASTY, upward 

 curvature due to increased il- 

 lumination. Photo - epinasty 

 and photo - hyponasty should 

 be distinguished from heliot- 

 ropism, as the curvatures are 

 in the directions stated, from 

 whatever direction the light 

 comes. 



PHOTOTAX'tS, taking a definite 

 position with reference to the 

 incident rays of light, as cer- 

 tain desmids and the leaves of 

 the compass-plant, Silphium 

 laciniatum. 



PHOTOTdN'fC, a term applied to 

 the stimulating influence of 

 light upon plants, inducing or 

 increasing irritability and ex- 

 citability. Thus, when growth 

 which has been arrested by 

 prolonged darkness is restored 

 upon admission of light, the 

 effect is termed the phototonic 

 influence of the light; with 

 most organs, however, growth 

 is more rapid in darkness. 

 This effect of light in retard- 

 ing growth is called its para- 

 129 



