THE  AMEEICAN 
JOURNAL  OF  PHARMACY 
SEPTEMBER,  1915 
THE  COMPARATIVE  MORPHOLOGY,  TAXONOMY,  AND 
DISTRIBUTION  OF  THE  MYRICACEjE  OF  THE 
EASTERN  UNITED  STATES^V 
/v 
By  Heber  W.  Youngken,  Ph.Ip. 
Along  the  eastern  seaboard  of  the  United  St\tes^ther< 
good  species  of  Myricacew,  and  a  hybrid  between  ft 
Myrica  cerifera,  Linne,  varies  from  a  low  shrub  to  a  tree  12  metres 
high,  and  extends  northward,  contrary  to  past  statements,  as  far  as 
Tuckahoe,  New  Jersey.  The  writer  finds  this  species  to  be  strictly 
evergreen  and  wholly  confined  to  coastal  regions  within  sight  of 
the  sea. 
Myrica  Caroliniensis,  Miller,  with  which  the  previous  named 
species  has  often  been  confounded,  is  strictly  deciduous,  except  when 
strong  basal  shoots  are  formed.  The  leaves  on  these  may  be  sub- 
evergreen. 
The  lanceolate  leaves  of  Myrica  cerifera  drop  without  assuming 
a  copper-red  color.  The  elliptic-obovate  leaves  of  Myrica  Carolini- 
ensis assume  a  greenish-brown  hue  on  an  extensive  scale  in  October 
and  November,  previous  to  leaf-fall.  This  species  is  of  wide  dis- 
tribution along  the  coastal  plain,  and  even  ascends  to  1200  feet  at 
Mount  Desert. 
A  hybrid  between  the  two  above  species,  Myrica  Macfarlanei, 
Youngken,  is  frequent  where  both  parents  abound.  Its  characteristics 
follow : 
Root  (secondary  structure). — The  hybrid  root  resembles  both 
parents  in  respect  to  its  cork,  its  cells  containing  gummy  lignin. 
Actinomyces  in  ducts,  barred  septa  and  crystal  fibres  accompany- 
*  Abstract  of  a  thesis  presented  by  the  writer  to  the  Faculty  of  the 
Graduate  School,  University  of  Pennsylvania,  May,  1915,  in  partial  fulfil- 
ment of  the  requirements  for  the  degree  of  Doctor  of  Philosophy. 
(39i) 
