THE ANATOMY OF THE NODE IN ANGIOSPERMS 315 
vaceae and Sterculiaceae being characterized almost exclusively by a 
trilacunar node. The only exceptions noted to this were among a 
few of the Malvaceae which possessed five or more strands. 
Parietales 
The Parietales are another rather large and heterogeneous order. 
The families included by Engler under the Theineae are various in their 
nodal anatomy ; the Eucryphiaceae and Ochnaceae being trilacunar, the 
Dipterocarpaceae having three or five bundles and gaps and the Marc- 
graviaceae,Theaceae and Guttiferae {fig. 21) being entirely unilacunar. 
The Dilleniaceae present another good example of a family which is 
intermediate between a trilacunar and a unilacunar condition. The 
genera Dillenia, Tetracera, Davilla, Curatella, Doliocarpus and Hib- 
bertia have either three or five bundles and gaps at the node. They 
all belong to the sub-family Dillenioideae which, from the simple 
structure of the stamens and the partial freedom of the carpels, is with 
little doubt to be regarded as more primitive than the rest of the family. 
The other two sub-families, the Actinidioideae and Saurauioideae, are 
more specialized florally and the two genera Actinidia and Saurauia 
which compose them are both unilacunar in nodal structure. The 
Dilleniaceae thus present further evidence that the unilacunar con- 
dition of the node has been derived from a trilacunar one. All the 
Cistaceae examined are unilacunar, but the Bixaceae, included with 
them under the sub-order Cistineae, are trilacunar. AH' members of 
the Flacourtiineae investigated (Violaceae, Flacourtiaceae, Stachy- 
uraceae and Passifloraceae) were trilacunar. The Caricaceae have 
from three to many bundles and gaps at the node. The number in 
the Begoniaceae is usually five. 
Opuntiales 
The Cactaceae are so much reduced that nodal anatomy is of little 
value in determining relationships. 
Myrtiflorae 
Aside from the Centrospermae, the Myrtiflorae are the largest 
order of Archichlamydeae to be overwhelmingly unilacunar. Most 
of the families grouped under the order by Engler were investigated 
and in all but three the departure of the foliar supply caused but a 
