GLOSSARY. 



921 



Protandrous, Proterandrous, used of flowers when 

 the anthers dehisce before the stigmas are receptive. 



Proteid, a nitrogenous substance of complex constitu- 

 tion, generally of a viscid nature and rarely crystal- 

 lizable. The proteids include albumin, globulin, 

 peptone, &c. 



Prothallus, -ium, the structure produced by the ger- 

 mination of the spore of Ferns, bearing sexual organs, 

 and from which tlie young plant arises and derives 

 nourishment for a time ; also the homologue of this 

 in flowering plants. 



Protogynous, Proterogynous, used of flowers in 

 which the stigmas are receptive before the pollen of 

 the same flower is discharged. 



Protonema, the filamentous growth of a Moss from 

 which the leafy shoots arise by budding. 



Protoplasm, the living and formative organic sub- 

 stance of plants and animals ; living matter in its 

 simplest form, serving as the basis of both animals 

 and plants, and consisting of carbon, oxygen, hy- 

 drogen, and nitrogen, colourless, transparent or 

 nearly so, and somewhat viscid in consistence. 



Protoplast, the protoplasmic cell-body; a simple one- 

 celled organism. 



Pseudo- hermaphrodite flowers are such as have 

 been functionally unisexual by the suppressing of 

 either stamens or carpels. 



Pseudomorph, a term borrowed from mineralogy; 

 an unusual or altered form. Cf. vol. i. p. 185. 



Pulverulent, powdery. 



Pulvinate, cushion-like. 



Pulvinus, the enlargement of a petiole or leaf -stalk 

 at its point of insertion on the stem, or of a second- 

 ary petiole at its point of insertion on the leaf-rachis. 



Pycnidium, in Fungi; a receptacle or cavity of vary- 

 ing form, in which conidia (pycno-conidia) are pro- 

 duced : especially in Ascomycetes. 



Pyrenoids, refractive bodies imbedded in the chloro- 

 phyll of many Green Algae, 



Race, a variety or form not distinguished by characters 

 important enough to rank as a species, but repro- 

 duced by seed and transmitting its characters to 

 the offspring ; also loosely used for a group of allied 

 individuals without regard to rank. 



Racemus, Raceme, an indefinite or centripetal 

 inflorescence with pedicellate flowers. 



Rachis, the axis of a compound leaf, or of a spike or 

 other indefinite inflorescence. 



Radical, belonging to or arising from a root, or from 

 a root-like portion of the stem below the ground. 



Radices adligantes, clinging roots. 



Radices columnares, columnar roots. 



Radices fulcrantes, stilt-like roots. 



Radices parietiformes, or tabular roots. See vol. i. 

 p. 754. 



Radices tuberosse, or tuberous roots; roots beset 

 with tuber-like enlargements. 



Radicle, the root of an embryo; usually not separ- 

 able from the hypocotyl. 



Radix, the root. 



Raphe, that part of the stalk of an anatropous ovule 

 which is fused with the body of the ovule ; in Dia- 

 toms, the median line on the frustule, possibly a 

 slit. 



Receptacle, of a flower; the abbreviated or flattened 

 axis upon which the various floral members are 

 inserted. 



Reniform, kidney-shaped. 



Replum, the framework, or fmmelike placvitU, 

 winch remams ni Cruciferous and other fnuU tdtet 

 the valves have fallen away. 



Resilient, springing back, rebounding: xmnl of fruit- 

 stalks, stamens, &c. 



Resin-duct, an intercellular passage into which 

 resin is secreted and where it is Btored. 



Respiration, the term applied to the alworption by a 

 plant of free oxygen from, and evolution of carlwn 

 dioxide into the air. It is the outward nitni of a 

 destructive oxidative process going on within iJic 

 plant, by means of which latent enorgj- in ren<len.-d 

 available. 



Revert, Reversion, a sudden return or breaking batk 

 to an ancestral form. 



Revolver-flowers. See vol. ii. p. 219. 



Rhizoids, the hair-like filaments of Mowm-s and 

 Liverworts, which perform the functions of nxit*. 



Rhizome, an underground (or prostrate) stem of 

 root-like appearance from wliich roots and her- 

 baceous stems arise. 



Rhizomorph, name given to the curious vegetative 

 phase of Agaricus melleus, which resembles a root. 



Rhizophore, a leafless branch of peculiar construc- 

 tion which, in Selaginella, arises at the place where 

 ordinary branching takes place, and bears roots at 

 its free end. 



Rhizotomoi, a guild of herbalists in ancient Greece. 



Ring, Annual, the zone of wood formed from the 

 cambium in the course of one season in a Conifer or 

 Dicotyledon. 



Ringent, gaping, as the mouth of a bilabiate corolla. 



Ringing, the act of removing from a bninch or trunk 

 a circular zone of bark right down to the wood. 



Root-cap, the cellular cushion produced at the ajwx 

 or tip of a root. 



Root-stock. Same as rhizome. 



Rostellum, the morphological apex of the gjTiopccum 

 of an Orchid ; usuallj' a beak forming the boundary 

 between the stamen and stigma in Orchids, 



Rosulate, collected in form of a rosette. 



Rotate, wheel-shaped; circular and horizontally 

 spreading. 



Runner, a prostrate filiform branch which is disposed 

 to root at the end or elsewhere. 



Samara, an indehiscent winged fruit, as the key of 

 the Ash or Maple, 



Saprophyte, a plant which grows on dead and dc 

 caj'ing organic matter. 



Scabrous, rough to the touch. 



Scape, or Scapus, a peduncle rising from the ground. 



Scarious, thin, dry, and membranaceous, and not 

 green. 



Schizocarp, a polycarpellary fruit which breaks into 

 1 -seeded portions. 



Sclerotic -cell, a hard, thick-walled cell, nft<?n of 

 irregular form ; sclerotic cells may Ixj united to- 

 gether into layers, or isolaUxl in soft i>arcnch>Tn». 



Sclerotium, in Fungi a tuber-like mass of hyphw, 

 which, after remaining dormant for a while, ulti- 

 mately sprouts, producing fructificition*. In lh« 

 Myxomycetes it is the rtrsting-stage of iho pU«- 

 modium. 



Scorpioid cyme, a definite inflor««cence mllrd up 

 towards one side like a crook : common in Uoragi- 



