Positive Heliotropism OF BOTANICAL TERMS. 



Primitive 



Geotropism. Compare Nega- 

 tive Geotropism. 



P6§'lT!VE HELlOT'ROPiSM, the 



same as Heliotropism. Com- 

 pare Negative Heliotro- 

 pism. 



P6§'lTIVELt RHEOTROP'IC, 



having the direction of growth 

 in a rheotropic organ coin- 

 cide with that of the stream 

 in which it is placed, i.e., 

 point down -stream. (Jonsson.) 

 Compare Negatively Rheo- 

 tropic. 



PdSTE'Rf OK, the side of a flower, 

 etc., adjoining the axis or main 

 stem. Compare Aktekior 

 and Dorsal. 



PdS'TfCOUS, see Extrorse. 



POUCH, see Silicle. 



POUCH-SHAPED, like a short hag, 

 as the pod of shepherd 's-purse. 



PRJE'CdX, see Precocious. 



PRiEFLORA'TION, see ^Estiva- 

 tion. 



PRjSFOLlA'TION, see Verna- 

 tion. 



PR2EM0RSE', see Premorse. 



PRATEN'SIS, growing in mead- 

 ows. 



FRECO'CIOUS, appearing or ripen- 

 ing before the proper or usual 

 time: said of flowers which 

 expand before the leaves, and 

 of plants which flower or fruit 

 much younger than usual, etc. 



PREFLORA'TION, see ^Estiva- 

 tion. 



PREFOLlA'TION, see Verna- 

 tion. 



PREM6RSE', abrupt, and irregu- 

 larly notched at the end as if 

 bitten off. Compare Trun- 

 cate. 



PRlCK'LE, a small, sharp, stiff 

 outgrowth from the epidermis. 

 Compare Spine and Thorn. 



PRl'MARt, chief or first formed. 

 For examples see Primary 

 Axis, Primary Cortex, etc. 



PRI MARt AX'IS, the main stem. 



PRl'MARt CORTEX, the true 

 cortex or fundamental tissue 

 of the bark. Compare Sec- 

 ondary Cortex. See Peri- 

 blem. 



PRl'MARt LEAVEg, see Primor- 

 dial Leaves. 



PRl'MARt MER'tSTEM, the 

 growing tissue of a young 

 organ. Compare Secondary 

 Meristem. 



PRI MARt PET'lOLE, the mid- 

 rib of a compound leaf. 



PRl'MARt ROOT, the central or 

 main root, being a direct con- 

 tinuation of the stem ; tap-root. 



PRl'MARt STRUCTURE, the 

 early structure of a plant or 

 organ after all its distinctive 

 tissues are formed and before 

 any further growth or modifi- 

 cation takes place. 



PRl'MARt TlS'SUE, (1) tissue in 

 the condition when first form- 

 ed; (2) that which is formed 

 during the first stage or season 

 of growth. 



PRl'MARt WOOD, that con- 

 tained in the fibrovascular 

 bundles of exogens when first 

 developed, before the forma- 

 tion of the cambium ring. 

 Compare Secondary Wood. 



PRI'MINE, the outer coat of the 

 ovule, called testa in the seed. 

 Mirhel applied the term pri- 

 mine to the inner coat of the 

 ovule, because first formed, 

 and some other German wri- 

 ters have used it in the same 

 sense. 



PRIMITIVE, original: applied, 

 for example, to the original 

 species from which cultivated 

 plants have been derived. 



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