28 Sargant . — Theory of the Origin of Monocotyledons 
sition exactly as those of Anemarrhena (Diagram VI), and 
the median bundle plays the same part that it does in Aspho- 
delits fistidosus. The root sometimes becomes pentarch in 
the same way. 
More commonly, however, a plumular trace — the midrib 
of the first leaf — enters the hypocotyledonary stele directly 
opposite the median trace of the cotyledon, and divides its 
xylem between the adjacent branches from the main cotyle- 
donary traces. The phloem of this plumular trace is con- 
tinued downwards into the root-stele without division. When 
this occurs the root is hexarch. 
In all the species hitherto described from this tribe, two 
main bundles are present in the cotyledon. Their identity 
with the bundles of Anemarrhena cannot be mistaken, in spite 
of the irregularities introduced by the entrance of plumular 
traces, or a minor cotyledonary trace, into the hypocotyl. 
Of the four species examined, but not yet described, Bulbine 
annua may be dismissed at once. The symmetry of the 
triarch root is determined by the three traces of the first leaf. 
The two distinct cotyledonary traces are inserted on two of 
them, and the transition follows Van Tieghem’s type 3. 
Three species remain, Chlorogaluni pomeridianum , Antheri- 
cum Liliago , and Arthropodium cirrhatum . The two main 
bundles of the cotyledon appear in all of them, but they 
are much reduced, and are associated in the hypocotyl with 
plumular traces which take a well-defined part in the tran- 
sition. I have examined no forms which are clearly inter- 
mediate between Anemarrhena and Chlorogalum. Such a 
series as that which leads step by step from Albuca to Muscari 
armenaicum (Plates I and II) would, however, account 
completely for the structure of Chlorogalum , and probably 
such a series of links either exists now or has once existed. 
Arthropodium is quite clearly linked to the less reduced 
Chlorogalum through Anthericum. 
Chlorogalum pomeridianum. The cotyledon, which remains 
underground and within the seed to the end (PI. IV, Fig. 1), 
