





272 DB. M. T. MASTERS ON THE MOBPHOLOGY, 



is conoidal or globular, in Pines cylindric, domical, acuminate, 

 covered with resin or not, and so on. 



In most species of Abies and Picea the bud-scales are more or 

 less coriaceous and oblong ; in Pinus there is a " mother " scale 

 succeeded by two lateral scales at the base, followed in spiral 

 order by 5 or 6 or more scales, which present great variations in 

 texture and duration, being long, tbia, and membranous in 

 P. Cembra, P. excelsa, &c, prolonged into a long acumen in 

 P. Coulteri, subcoriaceous and entire in Picea polita, &c, or 

 papery and lacerate at the edges, straight or ultimately re volute 

 at the tips, as in Pinus Bungeana and P. monophylla, &c. 



As these perulae serve a uniform and a temporary purpose 

 only they are less liable to variation and modification during 

 growth from the operation of external causes than organs of 

 longer duration and more complex function, and hence from 

 their relative invariability their utility for classificatory purposes 

 is greater than might at first be supposed *. 



Deperulation. — The manner in which the bud-scales are 

 removed or thrust aside by the growing shoot is also worthy of 

 attention. The variations observed depend of course on the 

 relation between the nature of the scales, the amount of resist- 

 ance they offer, and the degree of vigour and direction of 

 growth in the bud beneath. The " characters " so afforded 

 supply indications of a general tendency rather than of absolute 

 constancy. In some cases the bud-scales are least resistent to 

 the pressure of the growing shoot at the apex of the bud, in 

 which case the shoot makes its way through a ring or tube of 

 scales which persists around the base of the branch for a long 

 period. This method of deperulation may be called tubular. 

 Illustrations of it occur in Abies amabilis, brachyphylla, bifida, 

 Veitchii, homolepis, cephalonica, nob Ms, magnified, Lowiana, 

 concolor, Pinsapo, bracteata, Fraseri, Pseudotsuga Douglasii, 

 Picea ajanensis, polita, rubra, nigra, Engelmanni, Morinda, 

 Menziesii, and most species of Pinus, 



The phyllotaxis of the bud-scales is treated of by Henry in his classical 

 paper entitled "Beitrage zur Kenntniss der Laubkno8pen, ,, in Act. Acad. Nat. 

 Cur. xix. p. 1 (1837;, c tab. ; see also Eicbler, Entgegnung &c. in Sitzungsb* d. 

 Gesellschaft Naturf. Preunde zu Berlin, June 1882, p. 90. The adapta- 

 tion of the bud -scales to climatal conditions is tbe subject of a paper by Griiss, 

 " Die Knospen Schuppen d. Ooniferen u. deren Anpassung an Standort und 

 Clima," Berlin, 1885, a paper, however, of which I have only seen the title. 

 Menge, " Ueber d. Blattscheide der Nadeln von Pinus silvestris" 





















. 















* 









