110 



Miscellanea 



of these has a clustered group at thc top «ith one small lateral flower sonie distance down 

 the stem, anJ the other a clustered group with two lateral flowers in a lower position. Several 

 plants bearing seven flowers were found ncar the spot mentioned by Gerard as "Cray hoath." 

 It seems stränge that Gerard sliould give the numbcrs as tivc to scven wlien the four-flowered 

 inflorescences occur niore thaii twice as often as either the six-flowered er the seven-flowered. 



IL Vanation in the number of petuls. 



Before considering the Variation in the number of {Metals it would be as well to say a few 

 words about the niode of arrangement of the parts of a flower of the normal type. 



The tips of each of the uppermost petals of the four pentaiuerous lateral flowers (1, Diagram II) 

 fit into the space betweeii two i)etals (4) of the terminal and tetramerous flower. 



DiAOBAM II. Plan and side view of infiorescence without terminal flower. 



The arrangement of the reraaining petals is sliowii in Diagram II, where the pet;il indicated 

 by 2' in the expanded lateral flower shown in the diagram touchea petiil 2 of the flower on 

 the left band, while ])ctal 2 of flower A touches 2' of it-s neighbour on the right. The jietals 

 marked 3 and 3' touch in a similar manner. 



The Order in which the various flowers and petals in an infiorescence geuerally ojwn is very 

 curious. First, the four petals of the terminal flower e.\pand sinniltJvneously, theii two lateral 

 buds which are dianietrically opposite (a and a') open, and finally the opening of the other pair of 

 buds (b and b') take-s place. The order in which the petals of the pentamerous flowers exi>and 

 is 1, 2 and 2', and 3 and 3'. Matheuiatical precision is nece.ssary where tlie flowers are packed 

 in such a neat fa-shion, otherwise the struggle for space would result in a haphazard arrangement 

 and consequently a loss of space. 



The terminal flower is the least variable of all. Out of 763 terminal Howers 754 (about 

 99 per cent.) were found to be tetramerous ; 4 being pentamerous and 5 trimerous. The fi.xity 

 in the numl>er of parts of the terminal flower is used for the pur[X)se of classifying and tabulating 

 the variations from the normal type as given in Table II. 



The numbcrs given in Table II. lines 16 — 20 deserve special iiotice. Line 16 shows that 

 420 inflorescences with 4 pentamerous lateral flowers (reprcsented by the entry 4 in column 5) 

 were noted. In line 17 whero tliere are 3 "tivcs" and 1 "four" in thc inflorcscenco the numl>cr 

 hiU4 droppcd to 125. In line 18 where there are 2 "fives" and 2 " fours'' the number is 59, and 

 lines 19 and 20 show a further decrease in the totals as the florets with four jietals take the 

 places of those with five. The same rule holds in cji-ses where the numbcrs of flowers in 

 the inflorasccnces are seven, six and four. 



