52 MANGROVE SWAMPS 
drica the calyx-lobes are bent away from the tip of the fruit, 
while those of Brugiera parviflora are erect. 
Key to the species. 
1. Flowers yellow or red, 2.5 to 5 centimeters long; seedlings more than 6 
millimeters in diameter; inflorescences with one flower each. 
2: Flowers susualign tedert > tous > Sra eed .. Bruguiera conjugata. 
2... Flowers usually tyellowyese no. 0/8 i. ss) Bruguiera sexangula. 
1. Flowers greenish yellow, about 1 centimeter in length; seedlings less 
than 6 millimeters in diameter. Inflorescences with two to five flowers. 
2. Sepals bent back from the apex of the fruit... Bruguiera cylindrica. 
2. Sepals erect on fruit, less than one-fourth the length of the ovary. 
Bruguiera parviflora. 
BRUGUIERA CONJUGATA (Linn.) Merr. and B. SEXANGULA (Lour.) 
Poir. 
These species are very similar, the chief difference between 
the two being in the color of the flowers, red in the first case 
and yellow in the second. These are the largest trees among 
the true mangroves. Full-grown individauls are from 40 to 65 
centimeters in diameter and from 18 to 23 meters in height. 
The trees have an erect habit and thick-ridged, very dark, 
almost black bark, which contains many large, brown, corky 
pustules. The inner bark is of much the same character and 
appearance as that of bakauan and contains about the same or 
a slightly larger amount of tannin. 
The wood is very much the same in structure and appearance 
as that of bakauan, except that it is lighter red. At a short 
distance from the base of the trees and extending out to a dis- 
tance often as great as 5 or 6 meters are many air roots or 
knees, which are formed by roots bending upward and may ex- 
tend 45 centimeters into the air. The seedlings are stouter and 
blunter than in the other trees of the family. They germinate 
and grow to a length of 15 to 25 centimeters before dropping 
from the tree. 
BRUGUIERA CONJUGATA (Linn.) Merr. (Plate XVIII). BUSAIN. 
Local names: Potétan (Mindoro, Bataan, Tayabas, Negros, Leyte, Zam- 
boanga, Basilan, and Cagayan); busai-ing (Tayabas); bakdu (Tinago 
Island and Zambales); bakduan (Mindoro); busi-ing (Mindoro); bakau 
(Negros); busdin or similar forms (Mindoro and Tayabas). 
The leaves of Bruguiera conjugata are elliptic or elliptic- 
oblong, pointed at the tip, the base wedge-shaped. When dry 
the upper surface is shiny, the lower surface dull. The flowers 
occur singly in the axils of the leaves and are 3 to 4 centimeters 
in length and when fully opened slightly over 3 centimeters 
in breadth. The calyx is bell-shaped, leathery in texture and 
