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EDMUND W. SINNOTT 
(Ailanthus) possess seven bundles and gaps, and the Burseraceae and 
Meliaceae five. Erythroxylon is unilacunar. The Malpighiaceae are 
prevaiHngly tiilacunar but a few genera (Bannisteria) have but a 
single gap. The Vochysiaceae, Tremandraceae and Polygalaceae are 
unilacunar. The large family Euphorbiaceae is prevailingly trilacunar, 
but certain genera (Ricinus) have more than three bundles and a few 
(Antidesma) only one. The order agrees with the great majority of 
Archichlamydeae in being fundamentally trilacunar. 
Sapindales 
Under the Sapindales are included a large number of sub-orders 
some of which are not very closely related to one another, and the 
anatomy of the node is consequently rather diverse among the various 
members of the order. 
The sub-orders Empetrineae, Buxineae, and Coriariineae are 
evidently entirely unilacunar. Among the families included under 
the Celastrineae both types are represented ; the Cyrillaceae and Celas- 
traceae {fig. i8) being unilacunar and the Staphyleaceae trilacunar. 
Most of the Aquifoliaceae (Nemopanthus, Byronia and most species 
of Ilex) {fig. 20) are unilacunar but, as we have previously noted, 
Ilex opaca {fig. 19) has three bundles and gaps. The Aceraceae, Hip- 
pocastanaceae and Sapindaceae, included under the Sapindineae, are 
all trilacunar so far as observed save for a few species of Aesculus 
where there may be five bundles and gaps. The Balsaminaceae are 
entirely unilacunar but the single trace is clearly tripartite. 
It is within such rather heterogeneous groups of plants as are 
included among the Sapindales that the anatomy of the node, which 
is so constant within individual families, will probably be found to 
be of much value in determining the composition and relationship of 
the various sub-orders. As at present constituted, the Sapindales 
apparently cannot be regarded as a very "natural" order. 
Rhamnales 
In this order the Rhamnales are entirely trilacunar, but the Vita- 
ceae examined have three, five or seven bundles and gaps. 
Malvales 
The various families included under the Malvales seem to be very 
similar in their nodal structure, the Elaeocarpaceae, Tiliaceae, Mai- 
