II. II\I(;-TII(IM,\S. - iMCUTlANA CliUSSKS, /thl 



.Y. .s7//r,'s///s (Ovulr l'.-iivnl) X -V. ,if/i„is (Pdllrii l>;irciil). 



A'^. syliM'^tris lias rouiiil pollen. 

 A', nf/lnia has oval pcilleii. 



AH F, coloivd Rrd. l'urplc. ;ni,l Tin-od Wliilcs havc |H)lion for f N. 



af/inis. 



F, p. cluslcr X F, P. clusler (inler se). 

 j'.t pianls V, : Purple, -'7; Tiiit>e(l ^^'hile. I-' (P. lower surfare, W. iipper 

 surface) no rccls. 



Farm : A'', a f finis. 

 Ilaliil : N. affinh. 



F, P. Long style X Fj P. Shorl slyle (inlerse). 



'2S plaiils 1\ : Purple, 25; Tinged While, ô ; (P. lower surface, W . iipper 

 surface) nu rcilx. 



Forni : A^. affinix. 



Habit : .V. a/'/inis. 



Seven microphotograplis of Pollen (ig. (1). 



Pollen of each Parent, Pollen of live V\ plants. 



Red is eliminaled. Color and long luhe secm lo repuise e.ich olhei- in lliis 

 cross, as in thaï between \'. s^nc/c/vc and A'. .-<///rc.></;vs. 



Ail the color(Hl Nicoliana spccics and variations ! hase c\dlivalcd show 

 Tp dislincl shndes in their colors, whelhei- Piidc Tobaccos or While wilh cclored 

 uuder surfaces, \vilh llie e\ce)dion ul (uie, a perennial, N. ylawu, wliich has 

 pure \<'llo\v lloNsers of uniforni evenness of sliade. 



Niriiliiina Pollen /'oiin>; 



.Much variely of forin is fouiid in Nicoliana pollen, l'he l'nbucuni section 

 has the grealesL variely of Ihose examined and is characlerised by the square 

 grains and sqnare-endeds ovals nol seen in the garden species and varieties. 



A', sylve-slrh has round pollen, numbers estimaled at H/Slbs lo '2/r)lhs ovali 

 thèse grains are perfect sphères and bigger than the oval grains. 



.V. n/finis. X. Snn'lrr;i\ IJieii- hybrids, and .A', riri/llfnlin, ail bave oval 

 pollen. 



A. .s»'n'C(i/c/(s, an auslralian species wilh a distinct slructural différence froni 

 ail olher Nicoliana, naniely four sessile anthers and 1 fiee anlher, has oval 

 pollen, liut Ihe grains in Ihis species are much larger llian Ihe oval pollen of 

 any of the olhers. 



A^ glauca, a perennial, bas oval [iullen, anioni^sl Iheni au e(piilaieral 

 Iriangular form is seen which is conslanl. 



A trefoil pollen grain is seen in ail Nii-nliaua, soiue limes (uie iu Iweiily, 

 sonie limes one in fifly. but always présent iu every species and variely; lliis 

 li'efoil form is ciinsl,-inl . 



Si'ijir-(/(iliiin (iccurs w lieu r(Miud and oMibbeariug species are crossed : also 

 when s(piare and oval bearing species are ciossed. 



It was noliced,al the end of a sullry day, thaï in blossonis of A', xi/loeslris 

 Ihe number of l'oiiud grains was less, evaporalioii was rupposed to be thecause. 

 The followiug c\pcriuUMd> \\ere made lo lesl Ihis hypolhesis. 



