1907] GATES—POLLEN DEVELOPMENT AND MUTATION 99 
divisions. He remarks that these are chiefly cultivated plants, and 
suggests that the extra nuclei are indications of greater variability 
in structure resulting from cultivation. This was of course before 
the modern views of chromosome reduction and alteration of genera- 
tions had been developed. The fact that extra nuclei are so com- 
monly found among the irregularities in the divisions of the pollen 
mother cells in hybrids, together with the well-known fact that culti- 
vated plants are very commonly hybridized, would seem to lay open 
to suspicion the purity of any species in which such irregularities 
occur. Even Hemerocallis fulva, which is commonly quoted as a pure 
species having these irregularities, is well known to have been long 
under cultivation, and three varities of it are described by BAILEY (2). 
The other members of the list given by WILLE (I. c. 60), with men- 
tion of their cultivation and varieties, taken from BAILEY’s Cyclopedia 
oj American Horticulture, are given below. 
Name Varieties 
Ampelopsis hederacea 
=A. Quiriquefola .......+<.~: cult. climbing vine 
ech AGIA ee ye goes eee: ae cult. and hybridized 
BP ies cis cecans 2 he eerie acess es cult. and variable 
Charteania ey aga bine tals Te , not in Bailey 
ok ee cet nae 2 cult. shru 
Blatine he Bee sea ge not in Bailey 
Ficaria Secrcusenien phen aoe. - not in Bailey 
cn ee aL enn ‘ cult., very variable, and probably 
hybridized 
OONAER Sig Se eee asd od Sees 14 t. 
Hemerocallis fulva.............- 3 t. 
Lonicera coerulea............... ae cult. shrubs 
PRUNHNG MEFESUS.... 5 55 6 ens sods ie cult. and hybridized 
Rumex p: Mate he ees - cult. and nat. 
Scleranthus annuus............. = not in Bailey 
Stellaria (ds a © etek not in Bailey 
P m gaa ee a ths.) ba I cult. 
Syringa persica................. 2 cult. 
An examination of the list shows that all but five are forms culti- 
vated in America, and most of these are either open to suspicion 
as hybrids or known to have been hybridized. In the light of these 
facts, a careful examination of the history of all forms in which such 
extra nuclei are known to occur would be advantageous. It would 
4 Two other varieties are given by J. G. BAKER in “A revision of the species of 
herbaceous gamophyllous Liliaceae” in Jour. Linn. Soc. 11: 366. 1871. 
