MICHIGAN ACADEMY OF SCIENCE. 241 



I.iliales) we find a tricarpellary pistil (usually trilocular, sometimes 

 unilocular) mostly multiovulate, sometimes parviovulate, two (rarely one) 

 whorls of three stamens each, and three petals and three sepals, the 

 whole Hower usually axillary to a bract. 



If we study the different genera of the Liliales further we find that 

 there is a marked tendency toward a spicate arrangement of the flowers, 

 in which the flowers are reduced in size in proportion to their number 

 and crowding, the subtending bracts being proportionally larger with 

 reference to the flower. In certain families and genera (e. g. species of 

 Tillandsia) these bracts are two ranked and the small flowers are entirely 

 concealed by them except at anthesis when they gape apart a little and 

 allow stamens and stigmas and part of the perianth to appear. Spikes 

 of this sort are frequent in the Bromeliaceae and resemble enormous 

 spikelets of Eragrostis. In some of these plants the lowermost bracts 

 subtend only imperfectly developed or rudimentary flowers, then corre- 

 sponding perhaps to the two outer glumes of the grass spikelets. 



The occurrence in the Liliales of such spikelet-like structures made up 

 of two ranked bracts each subtending a small flower which in itself is 

 of the general Lily type (and sometimes with certain members missing) 

 would seem to indicate that the most primitive grasses must be sought 

 in those tribes in which these structures are most fully carried out. For 

 this reason my father, C. E. Bessey, long ago decided that the Bamboos 

 (Bambuseae) as a whole are the most primitive of the grass tribes. 

 Not all of the many genera of this tribe are equally primitive, for some 

 show a great degree of specialization. Indeed within this tribe there 

 seems to be less uniformity in floral structures than in any other grass 

 tribe, the vegetative structures, on the other hand, being remarkably 

 uniform. The more primitive bamboos possess spikelets with a very long 

 rachilla bearing a large number of florets. Sometimes several such 

 rachillae arise from one pair of glumes as sometimes happens in some 

 of the Bromeliads. The flowers (in some genera) possess three stigmas, 

 two whorls of three stamens each, three large lodicules which are even 

 petal-like in appearance. The palea, however, although sometimes 

 deeply cleft is united and the third sepal is missing. The pistil does 

 not always develop into the caryopsis found in the other grass tribes, 

 but in some cases is partially fleshy externally, forming in fact a sort 

 of drupe, and in others forms a nut, although mostly even in this tribe 

 the typical caryopsis is found. 



Thus, viewing the grasses from the standpoint of the Monocotyledoneae 

 as a whole it seems more reasonable to place the Bambuseae at the 

 base instead of at the apex of the family. (Fig. 12.) This emphasizes 

 the points of similarity and relationship with other groups of plants and 



