HISTOLOGY OF PHLOEM IN WOODY ANGIOSPERMS 
literature showed that there are also many published descriptions of 
sieve tubes of woody dicotyledons which do not agree with Hemen- 
way's classification. This led, in so far as time has allowed, to a 
checking of Hemenway's results in the woody dicotyledons by the 
careful examination of many of the species described by him. This 
has been taken up in addition to the seedling study originally planned. 
The following material has been examined. Collections marked 
N. S. followed by the age, indicate material taken from a branch of 
that age on a mature tree. Mature phloem with few exceptions was 
taken during the dormant season from thrifty trees ten inches or more 
in diameter. Growing material was also taken from mature trees. 
Mature root material was obtained from the larger roots of mature 
trees. 
List of Material Studied 
Acer Negundo L. 
Mature, twig. 
Acer rubrum L. 
Growing, twig. 
Acer saccharum Marsh. 
Mature, growing, mature root, 5-yr. 
stem, i-yr. stem. 
Aesculus Hippocastanum L. 
Mature, twig. 
Ailanthus glandulosa Desf. 
Mature, N. S. 5-yr., mature root, 
growing, 5-yr. stem, 5-yr. root, 
I- to 2-yr. stem, twig. 
Alnus incana (L.) Moench. 
Mature. 
Benzoin aestivale (L.) Nees. 
Mature, twig. 
Betula lutea Michx, f. 
Mature root, mature, 3-yr. stem, twig. 
Carya cordiformis (Wang.) K. Koch. 
Mature, 3-yr. stem. 
Carya glabra (Mill.) Spach. 
Mature root, 4-yr. stem, 3-yr. root, 
twig. 
Carya ovata (Mill.) K. Koch. 
i-yr. stem, i-yr. root. 
Castanea dentata (Marsh.) Borkh, 
Mature. 
Catalpa bignonioides Walt. 
Mature, twig. 
Celtis occidentalis L. 
Mature. 
Cephalanthus occidentalis L. 
Mature, mature root, growing, 2-yr. 
stem, 4-yr. root, twig. 
Cornus alternifolia L. f. 
Mature. 
6-yr. 
2-yr. 
Cornus Amomum Mill. 
2- yr. stem, 2-yr. root. 
Cornus paniculata L'Her. 
Mature root. 
Eleagnus angustifolia Pursh. 
Growing. 
Fagus grandijolia Ehrh. 
Mature, twig. 
Fraxinus americana L. 
Mature, mature root, growing, 
stem, 6-yr. root, 2-yr. stem, 
root, I-yr. twig. 
Fraxinus nigra Marsh. 
Mature, twig. 
Gleditsia triacanthos L. 
Mature. 
Gymnocladus dioica (L.) Koch. 
Twig. 
Juglans cinerea L. 
Mature, growing, mature root, 
stem, I-yr. root, twig. 
Juglans nigra L. 
Mature, N. S. 10, 8, 6, 4, 2-yr. 
stem, 4-yr. root, 2-yr. stem, 
root. 
Liriodendron Tulipifera L. 
Mature, mature root, 10- to 12-yr. 
stem, 10- to 12-yr. root, 3-yr. stem, 
3- to 4-yr. root, 3-yr. root, twig. 
Madura pomifera (Raf.) Schneider. 
Mature. 
Magnolia acuminata L. 
Mature, mature root, 12-yr. stem, 
5- to 7-yr. root, sucker shoot, 2-yr, 
twig. 
Morus alba L. 
Twig, mature. 
-yr. 
4-yr. 
2-yr. 
