





THE GARDENERS* CHRONICLE. 



,ff Mid" established in 4-inch pots previous to 



. f. ind in case that the cuttings are not fit for 



mdf early in autumn, it will be better to keep 



the winter in the cutting-pot. When potted 



ing autumn or spring, it will be neees- 



keep them rather warm and moist till they have 



e established. 



February, or early in March, place the young 



moist temperature of about 50°, and keep 



supplied with water. As soon as they 



heap, and to supply their places with 3 oung plants, as 

 11 kept after they become pot-bound, they seldom flower 

 satisfactorily. Alpha. 



pants 



f 1 



properly supplied witn water. 



muniB" p° win & examine tne 8tate U1 " ,c «w**i »"« 



^ift into pots two sizes larger such as require more 

 not. room. Water must be very carefully administered 

 tea week or two after potting, and the soil, as well as 

 tfce ball of the plants, must be in a proper state as to 

 BoUture when potted. If these important although 

 apparently trivial matters are rightly attended to, the 



voting P^° ts ™ n 80on burst int0 vi g orous growth, and 

 aboaU bellowed a free circulation of air during bright 



warm d$j*. It will probably be necessary to regulate 

 the growth by pinching-out the points of any over- 

 luxuriant fhoots, so as to secure a compact habit of 

 mirth. The Correa, like many other hard-wooded 

 plants, grows freely in a moist and moderately warm 



; bat when kept in a hot and dry tempera- 

 tore, the young wood becomes prematurely ripened, and 

 ill bealtii ensues. Perhaps the equal temperature and 

 atmosphere most congenial to the growth of the 

 plant ii more easily secured during the summer months 

 in a cold frame than elsewhere ; but the removal must 

 be carefully effected, and the plants should be kept freely 

 sallied with air for a time, previous to the change, and 

 the frame so managed as to maintain the temperature and 

 attDosphere sufficiently warm and moist to prevent them 

 ning any check. During summer, a slight shade on 

 the forenoon of bright days will be highly beneficial, and 

 the plants should be sprinkled over-head night and morn- 

 ing. Air should be freely admitted, except during the 

 occurrence of cold drying winds, when the lights should be 

 raised at the back only, and the temperature kept down 

 by means of shading. When the nights become warm, the 

 lights may be thrown off late in the evening, and again 

 replaced to protect the plants from the intense heat of 

 the sun's rays during the day. The stronger-growing 

 specimens may require a second shift towards August 

 or September ; and this should be attended to as soon 

 the pots are full of roots. Discontinue the fore- 

 aooa'i shade early in September, and gradually expose 

 the plants to the sun's rays and the freest possible 

 ♦irculation of air, merely guarding them from heavy 

 rams and autumn frosts. They should be removed to 



Jw*^? P&ft ° f the g reeDhouse ab °ut the middle of 

 October, where they may remain during the winter, and 

 will require no further attention than a supply of water 



and onttfh'nn fmm frost 



111! 



» ben they have 

 •*«J<1 be cut back, 

 •won as recommei 

 »t particularly di 

 •Wtered warm ail 



mm-tli k ' 1 *""*' "»»c uten excueu into acuve 



£wm by a close, moist atmosphere, they must not be 

 "W exposed to the drying winds and bright sunshine 

 JJ* frequently occur in May. When greenhouse 



E5 r l m ?' ed t0 the Plant-ground, they should be 

 r«w in a shady situation, and gradually prepared for 

 W exp« U re to the sun and air. During summer they 

 ■Jtbe freely supplied with water, and a sprinkling 



EK °w, C f VeniD S 8 of bri 8 ht da P ™» be 

 raim o«L 1 i e ni 8 hts become cold, or drenching 

 mi t»T' f 7 S , bonld be re n>oved to the greenhouse, 

 dewabl. ,! r K e]y ex P 08e <* to sun and air. If it is 

 in wiat.! Vu t* P ortion of the plants in flower early 

 «* W . 7, 8hould fe e placed in the warmest end of 



lf treated An. ** ^ M circum 8tances will permit. 



no , and if the young wood was properly 



D 



"Wed, then 

 ■ ? 'ney are 



^ODtlQQf 



any 



T tA rvl i_ " J w^^no. lfc Will UC UU 



»«^ed • Zt\fl them . m . h eat after the desired size i 



to ««rtin1 

 tobJono,, 



bnt '4* u ««*•* mict iuv uesireu size ig 



tn i 6 earl y- fl owering plants are induced 



of fl«rft m Wmter > & nd by these means a long 



*» SS^ wil1 be easil y secured - 



of thr * Pa«! 5 ° Und to thrive in a *° n composed 

 ***> wiftaf y P eat > and one P art Hght sandy turfy 



•*! loanj th fi mixtwe of silver 8and - The P eat 

 &«**> diT^M r H 6 carefull 7 bwken up into small 



«*sfan 



u v ^termix 

 P° te herda, hi 



^ioageo 

 BD place 



eB **nVm aa* ~!^. " 1C U1 ? Dai, » ana 8noma De ,n a proper 



J moisture when used. The plants 



In potting, the soil should be made 



*ill £Z? re « ard 



^iv 



more 



room ^ ^ 



^^ ta| r tl! >l00llai,,g 8ea * on win * - be comparatively 

 'Sof f &re P^^Uy unacquainted with 



l - with ^"P^nts wi| l act a wise part in resting 

 *• ^ riafc : JL? erate dis P la y of floral-beauty rather 

 l. Wi * an V ^ their P lanta ,ate m the season. 



^ **ich nT 8hift ' and atteQ tion to the simple 



?** *tov . • Just laid down » ^« ^rrea will 

 *Nif or ii/*** 1 ln P^ection, and. bv its abundant 



THE INFLUENCE of HEAT on the PROGRESS 



OF VEGETATION. 



{Concluded from p. 421.) 



I. Phases of Vegetation. — Very early in the course of 

 our inquiries we ascertained the curious fact that in the 

 valley of the Rhone a smaller sum of temperatures is 

 required to ripen Wheat than in the north of France ; 

 but that the Rhone Wheat had much shorter straw, and 

 was made up of a fewer number of joints than the other. 

 At Lougan on the Don, the straw is so high that an 

 ostrich can scarcely see over it ; but the sum of the 

 temperatures is very much greater. In Siberia Barley 

 ripens with a less sum of degrees than in the south of 

 Europe, but in the former country the return is only 

 three and a half fold, and the Barley, therefore, pro- 

 duces but a small number of spikelets in each ear, 

 whilst in France the return is eight or nine times the 

 quantity of seed sown. The above circumstances 

 appeared to show the direction which our inquiries 

 ought to take, and we determined to examine separately 

 each of the stages of vegetation, commencing with the 

 production of joints and then to compare each stage 

 with the temperature. 



The bud and the seed are alike an undeveloped plant 

 Both have a peculiar life distinct from that of other in- 

 dividuals of the same species. Both are rudimentary 

 branches. Both contain, wrapped one within the other, 

 the series of joints which when developed form a 

 branch. Each joint growing within the sheath contain- 

 ing it disengages itself in its turn from the centre of the 

 bud, and the formation and development of a joint may 

 be regarded as an elementary stage in the life of plants. 

 In the] first place, therefore, we determined to compare 

 the duration of this stage with the temperature accom- 

 panying it. The tables accompanying the memoir 

 show the results of observations made on the Mulberry 

 in 1840 and 1854 with this view. 



One year with another we obtained 66 joints on a 

 shoot from the stock of a hybrid multicaul Mulberry, 

 and the number of degrees was always nearly the same, 

 viz., 58.5° and 58.4° for the production of each joint 

 A shoot proceeding from a secondary branch pruned 

 nearly down to the stock gave only 44 joints, each of 

 which required 87.7° for its growth, although the shoot 

 was almost vertical. If, however, the shoot inclines 50° 

 from the vertical we obtain only 24 joints, each of 

 which requires 161° of temperature. The vertical 

 shoots of the top of old Mulberry trees pruned in the 

 spring have 27 or 29 leaves each, developing with from 

 133° to 143° of temperature. 



It thus appears that, 1, temperature has a direct 

 influence on the development of each joint ; 2, the 

 development of each joint requires pretty nearly the 

 same number of thermometrical degrees ; 3, the more 

 vertical the branch the fewer is the number of degrees ; 

 4, the number of degrees increases as the obstructions 

 to the flow of the sap to the bud are increased ; 5, 

 temperature does not act on the bud itself, but on the 

 sap which nourishes it, and the growth of a bud results 

 from the movement of the sap caused by temperature 

 and, the temperature being the same, the flow of the 

 sap to the bud is quick in proportion as its passage is 

 short, direct, and unobstructed. 



The joints, however, are not of equal length, and 

 their length does not depend on the influence of heat, 

 but on the quantity of sap which finds its way to the 

 plant, and which varies with the dryness and moisture 

 of the earth. This is at once evident if attention be 

 paid to the hygrometrical state of the soil ; after 

 rain the joints elongate, after drought they shorten. A 

 table for the year 1844 shows that in each month the 

 length of the joints varied with the temperature and 

 moisture of the atmosphere. It is, besides, known to 

 every one that rain makes plants grow ; a dry season 

 gives short spare hay, whilst after wet the crop is good. 

 A similar set of observations was made on the Beet- 

 root. The root has as many concentric circles as there 

 are spirals of leaves. In our first experiment we ob- 

 tained, from April to October, seven concentric circles 

 and seven spirals each of seven leaves ; the sum of 

 degrees of temperature was 3618, or about 100° per 

 joint. But the accumulation of matter resulting from 

 the abundance of sap is not regulated by the tempera- 

 ture. From the 1st of April to the 20th of Sept. Beet 

 was obtained weighing on an average 0.75 kil. During 

 the dry summer months there was a check, but on the 

 25th of October the roots weighed 1.05 kil. The 

 0.75 kil. were obtained with 3108° of heat and dry 

 weather, whilst the amount of 0.3 kit was obtained 

 with 510° under the influence of the rains of autumn. 

 Again, Beet-roots unchecked in their growth and placed 

 in a soil constantly damp (frais)^ acquired a weight of 

 3.5 kil. under the influence of 3618° of heat We must 

 be careful th 





which 



!£* 4* riant, ii re wmch ito culture requires 

 *H uS£^ me t0 ° '""go to be convenient!- 



** te better to throw them to the rubbish 



fore to distinguish increase of size from 

 production of organs ; the latter depends on tempera- 

 ture, the former on richness and abundance of sap. 



2. Flowering. — It is not absolutely necessary to the 

 life of plants that they should flower. Peas sown in 

 a highly manured soil ran into branches and leaves, but 

 did not flower. In the hot damp countries near the 

 equator Wheat does not ear, but yields so many stems 

 and leaves as to be cultivated for fodder. Humboldt 

 states that on the sides of the Cordillera of Vera Cruz, 

 near Acapulco, Wheat is not cultivated for its grain at a 

 less altitude than 1200 or 1300 yards. MM. Edwards 

 and Colin could not succeed in obtaining grain from a 



wiun r \\ heat sown at the end oi April ; but the MB*!! 

 spring Wheat and the still smaller seed of the small 

 winter variety sown at the same time both yielded ears 

 of corn. On the other hand Wheat is cultivated for its 

 grain in the Isle of France almost at the level of the 

 sea where the winter temperature is not below 26° 

 Cent, and is higher than that of Xalapa in Mexico, 

 where Wheat does not ear. M. Codazzi has seen 

 Wheat fructify in the valley of the Aragua, along with 

 sugar and coffee. M. Bremacker placed some Lilac 

 stocks in a dark cellar, in order to produce sleep arti- 

 ficially, and then removed them into earth in a hothouse, 

 where the temperature was moderate, and kept very 

 constant, but the plants ran to leaf and would not flower. 

 The experiments of MM. Edwards and Colin shows 

 that a large albumen disposes plants to produce leaves 

 only, just like the fertile soil in tbe case of the Peas, 

 whilst the less developed albumen of the spring and 

 poor winter Wheats yields ears, as happens with a 

 less rich soil. In M. Bremacker's experiment, the 

 constant moisture of the hothouse following the dampn 

 of the cellar was also followed by nothing but leaves. 

 We might thus expect to find a very moist atmosphere 

 on the Mexican side of the Cordilleras, and a succession 

 of moisture and dryness in those parts of the torrid 

 zone where corn ripens. At all events it is clear from 

 the above facts that flowering is by no means indispen- 

 eable to vegetation, and that a plant which receives 

 an abundant and continuous supply of sap is more 

 inclined to run entirely to leaf than to produce flowers. 



3. Ripeness of Seeds. — In the first place it is necessary 

 to ascertain what is meant by ripeness. Some say 

 fruit is ripe when it is ready to fall ; others require the 

 pericarp at least to be dried and the albumen to 

 be completely hardened ; others again allow fruit to 

 be ripe when the seed is so far advanced that it 

 can be made to germinate. This is ripeness in a 

 botanical sense, and is the only sense in which the 

 word can be used with precision. The period for gather- 

 ing does not depend on ripeness ; for example, the 

 Olive is either gathered or allowed to fall, according to 

 the purposes for which it is wanted. Grapes are 

 gathered when they are more or less ripe, according to 

 the object the grower has in view, the results expected 

 from fermentation, and the composition of the must, so 

 as to suit the tastes of bis customers. In Burgundy the 

 Grape harvest is later now than formerly, whilst the 

 contrary is the case in the south of France. As regards 

 Beans, it is usual not to cut them until the pod is 

 dry, but the farmers in the Valais, who desire to keep 

 the stalk unchanged, cut them as soon as the scar 

 of the seed is black, although the rest of it is 

 still green. Wheat seed has been proved by M. 

 Duchartre to be capable of germinating when the 

 albumen is still almost milky, and that germina- 

 tion was strikingly facilitated by the drying and 

 shrinking (retraction) of the corn. Without, however, 

 going so far as this, it is certain, from experiments 

 made at Versailles and La Saussaie, that corn may be 

 got in without inconvenience when the top of the stem 

 is still green, and that the grains are then finer and 

 more valued in the market. This sufficient ripeness 

 is from nine to 13 days earlier than what our farmers 

 call complete ripeness, and gives a sum of at least 245° 



of temperature. 



There is another difficulty met with when an attempt 

 is made to fix upon a sum of degrees of temperature as 

 necessary to enable a plant to arrive at maturity ; 

 namely, the difficulty arising from the great number of 

 varieties which mature, some faster and some slower 

 than others : this is the case with corn, Maize, Pota- 

 toes, Grapes, &c. We cannot therefore admit that 

 ripeness in its common sense, which is so arbitrary and 

 changeable, is a natural phase in the life of plants ; we 

 must confine the term to its botanical sense above 

 explained, concerning which we know very little, and 

 leave the rest to the convenience of cultivators. 



CONCLUSIONS. 



1. The successive phases of vegetation are marked 

 by the development of elementary organs, namely, 

 joints and their appendages, stem, leaves, buds, &c. 



2. The development of the joints is determined by a 

 sum of degrees of temperature, which is nearly constant 

 for the same species, and for branches whose position 



is alike. 



3. An indefinite number of leafy joints may be pro- 

 duced and yet the plant not flower. 



4. The number of such joints varies with the climate 



and the year. 



5. The flowering, and the number of leaf-bearing 

 joints which precede it, depend on the different circum- 

 stances which diminish the abundance of the sap in the 

 shoot, or which thicken it by compelling it to take long 

 or numerous indirect passages. 



6. As the meteorological conditions which influence 

 the sap — viz., the moisture of the soil and air, rain, 

 wind, &c, — are, on an average of several years, pretty 

 nearly the same in the same climate, plants flower with 

 tolerable regularity after having produced the same 

 number of joints. We are thus enabled to calculate 

 for a given climate the sum of degrees of temperature 

 which lead to flowering in the same climate, although 

 this number may not hold good for another climate 

 where the number of joints which precede the flowering 

 is no longer the same. 



7. Fructification and ripening being the consequencei 

 of flowering, the sum of degrees necessary to them also 

 varies with the climate. 



8. The time of harvest being always dependent on 



