522 GLOSSARY 



Ptyalin (Pty'-a-lin), an enzyme formed by certain animals which dissolves 



starch; it occurs in saliva, 133. 

 Pulvinus, a cushion, 87. 

 Putrefaction, decay of matter mostly by bacteria in the partial absence of 



air, producing foul odors, 141. 



Pyxidium (Pyx-id'-i-um), a capsule which opens by a lid, 209. 

 Raceme, an elongated flower cluster with numerous short lateral flower 



bearing branches along the main axis, 148, 149, 153. 

 Racemose, like a raceme. 



Radicle, the primary root of the embryo or seedling, 7, 13, 14. 

 Raphe, the portion of the stalk of an ovule which is joined to the ovule 



when the ovule is bent upon its stalk, 6, 201, 416. 

 Receptacle, in flowers the end of the stem to which the parts of the flowers 



are attached, 143, 156, 163, 166. 

 Regular, said of flowers when the members of the different series are equal 



in size and form, 146. 



Rhizoid, thread-like rootlets which serve as organs of attachment or absorp- 

 tion, or both, in the Thallophytes, Bryophytes and on the pro thallium 



of the fern plants, 335, 348, 365. 

 Rhizome, an underground root-stock, 48. 

 Root-stock, an underground stem, rhizome, 48. 

 Rotate, wheel-shaped, 146. 

 Salver-shaped, said of flowers in which the corolla forms a long tube from 



the end of which the lobes extend out at nearly right angles, 146. 

 Samara (Sa-ma'-ra), a dry fruit with a thin membranous expansion extending 



around or on one side. A "winged" fruit or "key" fruit, 206. 

 Saphrophyte (Sap'-ro-phyte), a plant which obtains its nutriment from 



dead or decaying organic matter, in, 134, 138-141. 

 Schizocarp (Schi'-zo-carp) , a dry fruit of several united carpels which 



splits at maturity so as to separate the carpels, 207. 

 Sclerenchyma (Scle-ren'-chyma), hard, stony tissue, 362, 363, 389. 

 Scorpioid cyme (Scor'-pi-oid), a flower cluster where the terminal flower 



opens first and the successive lateral branches arise on alternate sides 



of the "false" axis, 151, 152. 

 Scutellum (a little shield), the shield-shaped cotyledon of the grains and 



grasses, 13, 14, 18. 

 Sepal, a member of the series of parts of a flower making up the calyx, 143, 



152, 154, 158, 162. 



Septicidal, splitting through the partition between the locules, 208. 

 Septifragal (Sep-ti-fra'-gal), splitting at the partitions and separation of 



the partitions from the outer or dorsal wall of the carpels in a compound 



pistil, 208. 

 Silicic (Sil'-i-cle), a short silique, 209. 



