41 8 Introduction to Botany. 



of the chloroplasts, which derive their energy for the work from the hght 



absorbed by the chlorophyll. 

 Phyllo'dium (Gr. phyllon, leaf; eidos, form) : a petiole expanded into the 



form of a leaf blade. Fig, 261. 

 Phyl'lotaxy (Gr. phyllon, leaf; taxis, arrangement) : the angular distribution 



of leaves on the stem. 

 Phy'tomer (Gr. phyton, plant; meros, part) : a node with its leaf or leaves, 



and the internode subtending it. 

 Pi'lose (L. pilus, a hair) : beset with soft hairs. 

 Pin'na (L. pinna, a feather) : one of the primary divisions of a pinnate, or 



pinnately compound, leaf. 

 Pin'nate : compound, with the leaflets arranged on each side of a common 



petiole. Figs. 255 and 256. Oddly pinnate : with a single terminal leaf- 

 let. Fig. 255. Abruptly pinnate : all of the leaflets in pairs, and no ter- 

 minal leaflet present. Fig. 256. 

 Pinnat'ifid (L. pinna + jindere, fidi, to cut) : divided in a pinnate manner, 



but not as far as the midrib. Fig. 235. 

 Pin'nule : a secondary pinna. 

 Pis 'til (L. pistillum, a pestle) : the female spore-bearing leaf, or leaves 



united, of Spermatophytes, consisting of ovary, stigma, and commonly 



style. Fig. 87. 

 Pis'tillate : having pistils, and, as the term is commonly employed, destitute 



of stamens. 

 Pitted: having small depressions over the surface. 

 Placen'ta (L. placenta, a flat cake) ; that part of the interior of the ovary 



which bears the ovules. Figs. 302-305. 

 Plasm or plasma (Gr. plasma, anytliing formed or molded) : protoplasm ; the 



living part of the plant or animal body. 

 Plasma membrane : the limiting protoplasmic membrane at the exterior of 



plant cells which are destitute of cell walls, or the membrane which lies 



in immediate contact with the wall when the latter is present. Fig. 12. 

 Plasmo'dium : a multinucleated mass of protoplasm destitute of cell walls, and 



capable of amceboid movement. Fig. 132. 

 Plas'tid (Gr. plastis, plasiidos, a creator) : a differentiated portion of the cell 



protoplasm having definite work to do, such as the manufacture of starch, 



chlorophyll, and other pigments. 

 Pli'cate (L. plicars, to fold or plait) ; folded like a fan. 

 Plu'mose {X" plutna, a feather) : having hairs on each side like the plume of 



a feather. 

 Plu'mule (L. flumula, a little feather) : the first bud of the embryo. 

 Pod : a dry and dehiscent fruit, such as a legume or silique. Figs. 309 and 313. 



