446 
EDMUND W. SINNOTT AND IRVING W. BAILEY 
A perusal of this table makes plain the following facts. Of the 
75 families which possess stipules or leaf sheaths, 53 are charac- 
teristically tri- or multilacunar and in 5 others this type of node is 
very common. 16 of these stipulate families are characteristically 
unilacunar, but in 11 of them stipules are either very rare or minute, 
and in the others (Portulacaceae, Capparidaceae, Cistaceae, Logani- 
aceae and Rubiaceae) they are often poorly developed or absent. Of 
the 81 families, on the other hand, which are totally without stipules 
52 are characteristically unilacunar and 2 more are frequently so; 
and 27 have three or more traces. Of the 78 typically tri- or multi- 
lacunar families, 53 have stipules. Of the 70 typically unilacunar 
ones, 57 are without stipules and in the other 13 these structures 
are usually rare or inconspicuous. The families in which the leaf 
base is characteristically sheathing, such as the Polygonaceae, Arali- 
aceae and Umbelliferae, practically always have a multilacunar node. 
It is thus apparent that stipules and lateral leaf traces generally 
occur together. The exceptions to this rule will be discussed later. 
The following particular cases are of interest in showing the 
relation between nodal anatomy and the presence of stipules. 
The Polygonaceae are prevailingly multilacunar and in almost 
every case possess a stipular structure, the ochrea, which completely 
encircles the stem. The dioecious species of Rumex, however, are 
exceptional in the family in having a trilacunar node and also in 
possessing two typical and distinct stipules instead of an ochrea. 
The Aquifoliaceae are generally unilacunar and stipules are either 
absent or very small among them. In Ilex opaca, however, which 
has two lateral traces and gaps, the stipules reach their best develop- 
ment in the family. 
The Rosaceae are typically trilacunar and stipulate. Spiraea and 
its allies, however, are exceptional in being unilacunar and also 
exstipulate. 
Certain genera of the Dilleniaceae are trilacunar and others uni- 
lacunar. Stipules are generally absent in the family, but the few 
cases where they occur are only in the trilacunar genera. 
. Almost all of the Umbelliferae are multilacunar and have sheathing 
leaf-bases. Hydrococyle, however, is exceptional in being trilacunar 
and in having two typical and distinct stipules. 
The intimate connection between stipules and the two lateral 
bjandles of a trilacunar leaf-trace is therefore very apparent. A study 
