310 BOTANICAL GAZETTE [APRIL 
REPRODUCTION.—The more important studies of reproductive 
physiology and morphology in Taraxacum are so well known and 
so frequently cited that they require only brief comment here. 
1896. SCHWERE (22): embryo arises from egg in sac of typical 
appearance. 
1900. ANDERSSON and HEssELMAN (1): pollenless arctic 
specimens produce fruit, parthenogenesis suspected. 
1903. RAUNKIAER (18): “Species Danicae Taraxaci castratione 
agamice propagari demonstratum est; ‘species omnes Taraxaci 
semper parthenogenetice propagari verisimile est.”’ 
1904. KIRCHNER (13): pollen of Taraxacum never found 
germinating upon Taraxacum stigmas, although often abundant. 
1904. MuRBECK (15): confirms findings of SCHWERE, RAUN- 
KIAER, and KIRCHNER. Finds embryos in unopened, pollenless 
flowers. 
1904. JUEL (11): embryo sac maturation reduced to single 
division. Apparently no reduction, although prophase resembles 
1905. JUEL (12): compares maturation phenomena of sexual 
Chicoraceae with those of T. officinale (vulgare ?). Notes double 
thread in prophase of former but not in latter; former shows 
haploid number of bivalents in diakinesis, while Taraxacum shows 
diploid number (24-26) of univalents. These facts believed to 
favor the parasynaptic view of reduction. Following diakinesis in 
Taraxacum, nucleus is believed to elongate and chromosomes to 
split temporarily, the sequence being regarded as a shift from 
heterotypic to homotypic prophase. Pollen goes through reduction 
forming 12 or 13 bivalents in first prophase, but doubleness of 
spireme not observed. 
1907. HANDEL-MazetTtI (6): noteworthy monograph of genus. 
Emphasizes genetic importance of parthenogenesis, but believes 
RAUNKIAER’S conclusion too sweeping. Shows clearly that pollen 
development must be highly variable. 
1907. DAHLSTEDT (4): notes presence of numerous sterile 
seeds and surmises that normal eggs may be found in otherwise 
parthenogenetic heads. Also believes sexual species likely 10 
exist. 
