BOTANY. 



totally destitute of those, by which its 

 Species is propagated from generation to 

 generation ; for propagation by cuttings, 

 buds, or roots, is only the extension of 

 an individual, the life and vigour of which 

 gradually wears out, unless it be repro- 

 duced from seed. The fructification is, 

 therefore, well defined by Linnaeus, as " a 

 temporary part of vegetables, terminating 

 the old individual and beginning the new." 



The parts which constitute these es- 

 sential organs are seven. 1. Calyx, fig. 35, 

 the flower cup, or external covering of 

 the flower. This also is of seven kinds. 

 1. Periantldum, or calyx, properly so call- 

 ed when it is contiguous to and makes a 

 part of the flower, as the five green leaves 

 which encompass a rose, including their 

 urn-shaped base 2. Invohicnim, which is 

 remote from the flower, as in the umbel- 

 liferous tribe ; but if the idea of these 

 plants, as above expressed, be just, the 

 part in question ought rather to be con- 

 sidered as a bractea. 3. slmenturn, a cat- 

 kin, is formed of numerous scales attached 

 to one cylindrical receptacle, and falling 

 off with it: in catkins which bear seed 

 the scales are often enlarged, and har- 

 dened into a cone, as in the fir. 4. Spatha, 

 a sheath, bursts longitudinally, and is 

 more or less remote from the flower, as 

 in the snow-drop, narcissus, and arum. 



5. Gluma, a husk, is the peculiar chaffy 

 calyx of grasses and their allies: to it 

 belongs the arista or awn, which however 

 is not constant in the same species of 

 grass or corn : an elegant feathery awn is 

 seen in the stipa pennata, feather-grass. 



6. Perichoeiiumy a scaly sheath, investing 

 the fruit-stalk in some mosses, as hyp- 

 num. 7. J T olva t the wrapper of the Fun- 

 gus tribe, is either of a membranous 

 kind, sheltering their fructification, as in 

 the common mushroom, or more coria- 

 ceous, investing the base of their stalk, as 

 in many fungi. 



2. Corolla, fig. 56, the delicate, gene- 

 rally coloured, leaves of a flower are al- 

 ways situated within the calyx, when both 

 are present. This term comprehends 

 both the petal, petahtm, and the nectary, 

 iiectarium. A flower consists of one pe- 

 tal, or of several, the former, denominat- 

 ed monopetalous, is either campanulate, 

 funnel-shaped, salver-shaped, wheel- 

 shaped, ringent like the mouth of an 

 animal, or personate, closed by a palate. 

 Its parts are the tube and the limb. A 

 polypctalous corolla is cither cruciform, 

 as in a wall- flower, rosaceous, papiliona- 

 ceous, as in the pea-kind, or incomplete, 

 when some parts found in analogous 



V^ S^ \J I 1 3 j 



when 



flowers are wanting. The parts of a po- 

 lypetalous coro'la are the claw and the 

 border. The great point to be consider- 

 ed with respect to the corolla in general 

 is, whether it be regular or irregular : in 

 some flowers, however, it varies in the 

 same species from one shape to the other, 

 witness the genera antirrhinum and big- 

 nonia. 



JN either the calyx nor corolla is indis- 

 pensably necessary to a flower. Both are 

 wanting in hippuris, and one or other is 

 deficientin many genera. Hence botanists 

 are led into a perplexity, how, in some 

 cases, to denominate the part which is 

 present. When its green colour and 

 thick texture agree with the generality of 

 flower cups, we do not hesitate to esteem 

 it such ; but a calyx is often beautifully 

 coloured, and there is some doubt whe- 

 ther the splendid leaves of tulips and lilies 

 be not a true calyx ; at least they answer 

 to the Linnaean definition, that their parts 

 are opposite to the stamens, whereas 

 those of a corolla should be alternate with 

 the latter. The Linnaean hypothesis, how- 

 ever, though sanctioned by Jussieu, of 

 the corolla proceeding from the inner 

 bark, and the calyx from the outer, is en- 

 tirely subverted by recent and more cor- 

 rect observations on vegetable physiolo- 

 gy. The functions of these two parts are, 

 perhaps, though similar, not exactly ana- 

 logous. Those of the calyx probably re- 

 semble what are performed! by the leaves, 

 and this part is presumed by Dr Smith 

 even to secrete woody matter, for 

 strengthening the fruit-stalk. The co- 

 rolla, indeed, seems destined to ans\\ er 

 some exclusive purpose to the essential 

 organs of impregnation with regard to air 

 and light. It fades when they wither, and 

 is altogether of temporary duration, 



Nectariwn, the nectary, fig. 37, is fre- 

 quently a part of, or an appendage to, the 

 corolla ; sometimes ihe petal itself se- 

 cretes honey : sometimes a set of glands 

 perform this function ; and in other cases 

 there is a peculiar petal-like apparatus 

 for preparing or holding the nectarious 

 juice. Linna-us has remarked that plants, 

 whose nectary is distinct from the petals, 

 are commonly poisonous, which in gene- 

 ral holds good with those of the more ela- 

 borate nectaries. A German writer, 

 named Sprengel, has proved the corolla 

 to be in many instances an attraction, as 

 well as accommodation, for insects in their 

 search after honey: he remarks certain 

 spots, called by him maculte indicantes, 

 which he conceives are designed to di- 

 rect these little animals to their prey. 

 The scent of flowers may perhaps con- 



