ORGANS OF REPRODUCTION. 



73 



8. The flowers are sertulate, wlxen the pedun- 

 cles are simple, spring all from the same point, 

 and attain nearly the same height ; as in the 

 flowering rush, most of the species of allium, the 

 gemis primula, &c. This kind of inflorescence 

 has heen referred to the umbel ; but it differs so 

 much from that species as to deserve a name of 



its o^^^^. 



9. The flowers are disposed '^ 

 in a wliorl or are whorled or 

 verticillate, when they come 

 off around the stem at the 

 same height ; as in mare's tail. 



10. The Spadix is a species 

 of inflorescence, in which the 

 common peduncle is covered 

 with unisexual flowers, which 

 are naked, in other words, destitute of 

 a proper calyx, and generally distinct 

 and separated from each other ; as in 

 arum maculatum, caltlia palustris, &c. 

 Sometimes, however, there are observed 

 scales, which separate the flowers ; but 

 these cannot be considered as calyces, 

 as they spring from the substance of 

 the peduncle itself, of which they ap- 

 pear to be appendages, and are always 

 situated beneath the point at which 

 the flowers are attached; as in certain species 

 of pepper. The spadix is peculiar to the mono- 

 cotyledonous plants, and to the different species 

 oi piper. Sometimes it is naked, in other words, 

 destitute of a general envelope ; as in the genus 

 just mentioned. At other times, it is enveloped 

 in a spatha ; as in the aroidese, and certain spe- 

 cies of palms. 



11. The cathin is a kind of inflorescence, in 

 which unisexual flowers are '^■ 



inserted upon scales which, in 

 some measure, perform the 

 office of a peduncle. Flowers 

 so arranged are named amenta- 

 ceous. Of this kind are the male 

 flowers of the chestnut and 

 hasel, the male and female 

 flowers of wUlows, &c. This species of inflor- 

 escence is that observed in a whole family of 

 plants, composed of trees of various sizes, and 

 which are named amentaceous. Of this kind are 

 willows, poplars, alders, the birch, the hornbeam, 

 the oak, the beech. 



AU plants do not flower at the same period 

 of the year. There are, in reference to this cir- 

 cumstance, very remarkable differences, which 

 depend upon the nature of the plant, the in- 

 fluence of heat and light, and the geographical 

 position of the vegetable. Were they to come 

 out all in the same season, and at the same period, 

 they would disappear too soon, and vegetables 

 would remain too long destitute of their great- 

 est beauty. Even winter, notwithstanding the 



cold which accompanies it, is not without 

 flowers. The snowdrop, the hellebores, and 

 the mezereons, unfold their flowers when the 

 gi-ound is still covered with snow. These ex- 

 amples, however, may be considered as excep- 

 tions to the general order. Cold, in fact, ap- 

 pears to oppose the growth and expansion of 

 flowers, whereas a gentle and moderate heat 

 favours and maintains them. Accordingly, in 

 countries where the temperature continues in a 

 mean state the whole year, a kind of perpetual 

 spring prevails, and the earth is always covered 

 with new flowers. In the temperate parts of 

 Europe, it is in spring, when a gentle and vivify- 

 ing heat has succeeded to the cold of winter, that 

 the flowers gradually separating their envelopes, 

 expand and disclose their beauties to our view. 

 The months of May and June are those which 

 see the greatest number of flowers expand. 



According to the season in which they deve- 

 lope their flowers, plants have been distinguished 

 into four classes : — 1. Vernal, those which 

 flower during the months of March, April, and 

 May ; such as violets, primroses, &c. 2. ^stival 

 or summer plants, those which flower from tlie 

 beginning of June to the end of August. Tliese 

 constitute the great majority of plants. 3. 

 Autumnal, those which expand their flowers 

 from September to December. Of this kind are 

 many species of aster, and meadow saffron. 4. 

 Hibernal or winter plants, those which flower 

 from about the middle of December to the end 

 of February ; such as many mosses and junger- 

 mannise, the snow drop, black hellebore. 



From the consideration of the period at which 

 different plants produce their flowers, Linnaeus 

 formed his Calendar of Flora. For, there are 

 many plants whose flowers always appear regu- 

 larly at the same period of the year. Thus, in 

 the climate of Paris, the Christmas rose flowers 

 in January ; the hazel and mezereon in Feb- 

 ruary; the almond, the peach, and the apricot, 

 in March ; the pear, tulips, and hyacinths, in 

 April ; the lilac and the apple in May. 



Not only do the flowers show themselves at 

 different periods of the year, in different plants, 

 but there are many flowers wliich open and close 

 at determinate hours of the day, while some ex- 

 pand only at night. Thus the marvel of Peru 

 opens its flowers only when the sun has sunk be- 

 neath the horizon. Hence flowers are distin- 

 guished into diurnal and nocturnal. The latter 

 are much less nui^erous than the former. There 

 are even flowers which have the habit of open- 

 ing and closing at certain periods of the day, 

 with so much regularity, that one may tell the 

 hour by them. Linnaeus, who was so ingenious 

 in detecting the most interesting circumstances 

 respecting flowers, made iise of the periods at 

 which some species are well known to expand, 

 for the purpose of forming a table, to which ho 



