GLOSSARY. 257 



PLASTICITY Retaining any impressed form or shape. 



POLLEN (Bot.) The male element in flowering plants, usually a fine dust 

 produced by the anthers, which by contact with the stigma effects the 

 fecundation of the seeds. This impregnation is brought about by 

 tubes (pollen tubes) which issue from the pollen grains adhering to 

 the stigma and penetrate through the tissues until they reach the 

 ovary. 



POLYGAMUS PLANTS Plants in which some flowers are unisexual and 

 others hermaphrodite. 



POURRIDIE (Fretich) Disease on the roots of vines caused by different 

 fungi. 



PROCREATION Generation or production of young. 



PRODUCTIVITY The quality or state of being productive. 



PROTOPLASM More or less granular material of vegetable and animal cells, 

 the so-called "physical basis of life," the original cell substance. 



PROTUBERANCE A swelling or prominence, such as the protuberance of a 

 node. 



PUBESCENT Covered with fine short hairs, as the leaves of some vines. 



PYCNIDIA, sing. PICNIDIUM (Bot.) One of certain minute sporiferous 

 organs found in certain fungi. 



QUATERNARY TUFA (Geol.) A soft porous stone formed by deposition 

 from water, usually calcareous, belonging to the quaternary age. 



RADICEL (Bot.) A small branch of a root ; a rootlet. 



RAPHE or RHAPHE (Bot. ) The continuation of the seed stalk along the 

 side of an anatropous seed, forming a ridge or stem. 



REVERSION To return towards some ancestral type or character ; atavism. 



KIB (Bot.) The chief nerve or one of the chief nerves of a leaf ; also any 

 longitudinal ridge on a stem, as in V. Berlandieri. 



ROUNDED LEAF Having a curved outline without lobes. 



RUDIMENTARY Very imperfectly developed ; in an early stage of develop- 

 ment. 



RUGOSE, leaf Having the veinlets sunken and the spaces between them 

 elevated. 



SCHIST Any crystalline rock having a foliated structure. 



SCHISTOSE SOILS Are usually metamorphic clays. 



SCION A piece of branch cut for grafting into another. 



SEMI Prefix signifying half, as in semi-erect, semi-climbing habit, &c. 



SEPALS The leaves or segments of the calyx, or outermost envelope of an 

 ordinary flower. They are usually green. 



SHOULDERED GRAPES Those in which the two ramifications of the base 

 are well developed. 



SIEVE TUBES (Bot.) Also called cribriform tubes. Those having here and 

 there places perforated with many holes. 



SILICA Quartz, silicon dioxide. 



SILICEOUS NODULES See Nodule. 



SILICEOUS or SILICIOUS SOILS Those containing silica or quartz. 



SILURIAN (Geol.) A term applied to the earliest of the Palseozoic strata. 



SINUS (PI. SINI or SINUSES) A depression between adjoining lobes in a 

 leaf. 



SPECIES An ideal group of individuals which are believed to have 

 descended from common ancestors, which agree in essential characters 

 and are capable of indefinitely continued fertile reproduction through 

 the sexes. A species as thus defined differs from a variety or sub- 

 species only in the greater stability of its characters and in the absence 

 of individuals intermediate between the related groups. 



SPORANGIA, sing. SPORANGIUM (Bot.) A spore case in fungi. 



SPORE (Bot.) One of the minute grains in flowerless plants which are 

 analogous to seeds, as serving to reproduce the species. 



10890. B 



