BOTANY. 



above them in Enconus In some instances it resem- 

 bles the proper leaves, as in Mespilus ; but is often of 

 a membranous texture as in Helleborut. Jn some of 

 the Orckidetc the leaves are gradually resolved into 

 bracte, so that it is difficult to decide where the leaves 

 terminate, and the bracte commence. The chaff of 

 grasses are bracte. 



Of Involucre. This is allied to bracte, but as it 

 occurs conspicuously on umbelliferous plants, it is 

 deemed proper on this account to distinguish it by 

 this name. The involucre consists of one or more 

 leafy expansions, differing in shape from the prope 

 leaves of the plant, situate at the base of an umbel. 



Involucre of a phlox and Chinese primrose. 



When at the base of a compound umbel it is called 

 the general involucre, and when at the base of the 

 partial umbel the involucellum. The bracte of the 

 anemone has been supposed to be involucre, but this 

 is not. jjenerally allowed. 



Of the Soothe, This member is the membranous 

 covering which involves the flowers of the snowdrop, 

 onion, arum, and palms before their expansion. By 

 some botanists it is called bracte, by others involucre, 

 but as it is not decided which it really is, it is as well 

 to call it by the conventional term most generally 



known. 



Spathe. 



Narcissus. 



OftheTendril(Cirrhus\ The tendrils are those con 

 volvingstrings or claspers by which plants are occasion 

 ally supported. They are produced on different part 



f flexible stems, and attach themselves to other bodies 

 or the support of the plant ; on the grape-vine they 



are inserted from the young shoots opposite the 

 leaves, fig. 1 ; in the pea the points of the footstalk 

 of the leaves are resolved into compound tendrils, 

 fig. 2 ; the superb lily bears them on the points of the 

 leaves, fig. 14 ; and on the ivy they are short pro- 

 cesses issuing from the bark, fig. 4. 



Of the Annul arc. Plants are furnished with defen- 

 sive appendages called spines, prickles and stings. 



Spincx (Spin&) are woody processes issuing from 

 the stem, and appearing to be abortive shoots, as 

 those of the white thorn and wild crab apple ; from 

 the points of the leaves, as bntchers'-broom ; from 

 the calyx, as the thistle ; from the seed-vessel, as the 

 thorn apple ; and from the seed, as spinach. 



Prickles (Acnlcux') are situate on the bark, and 

 appear to be articulated therewith, as in the rose and 

 gooseberry. Sometimes they take the place of other 

 members of the plant, as instead of stipulae in the 

 berberry, and bastard acacia. In the genus Mam- 

 malaria and other succulent plants, prickles appear 

 to do the office of leaves. 



Stings (Stimuli) are a smaller kind of prickles, but 

 with this difference, they emit a poisonous juice into 

 the punctures made by them, causing painful irritation 

 and inflammation. Example, the common nettle. 



Glands are small protuberances seated on various 

 parts of plants. They are either secretory or excre- 

 tory organs. Fibrous roots are observed to issue 

 from those situate on the bark of the common laurel, 

 if the branch be layered in the ground. Professor 

 de Candolle remarks that these bear the same relation 

 to the roots that buds bear to young branches. They 

 are very conspicuous on the petioles of the peach, 

 and passion flower. Glands are described by bota- 

 nists under various names, as miliary, bladder, scaly, 

 lenticular, cup-shaped, and utricular, the latter being 

 very visible on the young shoots of the vine, and on 

 several species of fig-marigold, appearing like globes 

 of crystal. 



Pubescence. The exterior cuticle of plants is either 

 perfectly smooth and naked, or covered with hairs ; 

 in some cases, soft and fine as silk, as the silver tree 

 (Protca, argcntca) ; or rough and harsh (asper) when 

 the whole plant is covered with short rigid bristles, 

 as borage. Botanists employ many different terms 

 in describing this clothing of plants, viz., hirsute, 

 hairiness ; villosus, villous ; tomentosus, downy ; glochi- 

 <l fit its, barbed or bearded ; sericeus, silky ; arachnoid, 

 cobweb-like ; rostella, hooked, &c. 



Scales. The cuticle of some plants is profusely 

 covered with scale-like processes, giving a greyish 

 hue to the surface. They are microscopic objects, 

 and may be met with on the leaves of the pine-apple ; 

 plants bearing them are said to be leprous (kpidotus}. 

 Another cuticular excrescence of a scale-like charac- 

 ter is borne on the young shoots and backs of the 

 leaves of ferns, these are called ramenta. 



