28 University of ('alifoniid I'uhJications i)t Botany [^^o^- ''' 



structiiri's would vary ().") mm. or less l)('t\v('en different individuals. 

 The series jjiveu in tabU' 1 is suffieiently eomidete lo bring out the 

 points wliieli seem of most signifieance. 



If we lurn now to a description of the ai)pearance of these various 

 sizes of undevelopeil flowers. Hie more highly differentiated form — 

 numbiTs 1 lo () — might lirsl bi- mentioned. As stated above, these 

 larger undeveloped flowei-s ai'e really small, fully formed flower buds. 

 They are (piite conspicuous, standing in the center of the whorl of 

 leaves, with while, transparent, parehmeiit-like .sepals and petals. 

 Such "buds" never open and I'apidly dry down as the leaves are 

 fully expanded. The stamens are usually perfect in appearance with 

 anthers fully matured, 1 hough they are very slender and perfectly 

 white except along the pollen sacs, which are sometimes a very light 

 j^ellow in color. Pollen is often present in such cases with every grain 

 shriveled and functionless, while in other cases sporogenons tissue 

 apparently is suppressed entirely in the development of the anthers. 

 The ])istil in these lai-gest undeveloped flowers is always functionless 

 and often entirely wanting. Where if does occur the pistil is very 

 nuR'li reduced, with diminutive stylar tissue and with no ovules or 

 structures suggesting them in appearance. On T. ovatum. a 

 pedunculate species, such large undeveloped flowers at times are to 

 be seen and in these cases a peduncle is present proportional in size 

 to that of the bud. At times, however, this proportion is not main- 

 tained, and the small, white bud appears to be sessile, so short is 

 the peduncle upon which if is borne. There is a more or less abrupt 

 transition from the early withering, functionless bud that never 

 opens, although its parts are rather fully and characteristically 

 matured, to the small undeveloped flowers in which all the parts are 

 similar in appearance though differing greatly in size so far as the 

 different circles of perianth segments are concerned. As stated 

 above, the pistil even in the largest undeveloped flowers is often 

 suppressed, the sepals and petals are of the same color, texture and 

 size, and the remainder of the functionless bud consists of narrow, 

 delicate anther-bearing structures. If is in the differentiation of these 

 stamens of more or less characteristic appearance and sfi-uctui-e that 

 file rafhei- abinipt fi'ansition occurs. Thus all the smaller undeveloped 

 flowers consist of nothiug more than minute, white, di-y perianth 

 segments which are, in all but those of the smallest size, arranged 

 rather definitely in separate whorls. As shown in ]ilate 5, figure 2, 

 the smallest uTidevelojied flowers in some cases show a union of the 



