f)0 
RXHiniTION AND LEC'Tl’RR MEETINGS, 1951 
Hybrid Vigour in AS^PLENIUM ADIANTUM-NIGBUM L. 
fjive ])lants of Asple7iiinii Adiantvm -nigrum L. ssp. Adiantum-nig- 
nun, A. Adiantwm-nigrum L. ssp. onopteris (L.) Heiifl., and their arti- 
ficial hybrid, were exhibited. The three ferns were the same age (two 
years from fertilization), l)ut the hybrid showed immense ‘ hybrid 
vigour was veiy much larger than the ])arent s])ecies, and was par- 
tially sterile. 
Ss]i. Adiantum-nigmm is a tetrai)loid, with n = 72, and this plant 
was grown from spores collected in Cornwall, while ssp. onopteris is a 
diploid, with n = 36, and these spores came from Madeira. Photographs 
of nieiosis in the spore mothei'-cells of the trijiloid showed about 36 bi- 
valents and 36 univalents at metaphase, and lagging chromosomes at 
anaphase. The pairing of the chromosomes at metaphase suggests n 
close relationshi]) between the two Aspleniums, and it seems likely that 
ss]). onopteris is one of the parents of the widespread tetraploid s.s]). 
Adia n tum-nigr'um. 
Miss E. W. D.avies. 
CABEX BEMISSA Hor.nem. and CABEX HYBPIDS 
Carex demissn Hornem. seems to hybridize with C. flava L., C. 
lepidocarpa Tausch and C. serotina IMerat whenever it is found with 
or in clo.se proximity to these species. 
Herbarium specimens were exhibited as follows: — 
(\irex demissn Hornem., ('. ffara L. and various hybrid and inter- 
mediate forms from Houdsea Wood, Haverthwaite, Lancs. 
Gnrex demissn Hornem., C. seroHrw- Herat var. cyperoides Marss. and 
several hybrid forms from Shapwick peat moor, Somerset. 
In each locality the ('nrex demissn and the intermediate forms were 
more abundant than the C. flnva and C. serotina respectively, whicJi 
were rare, and it a])]ieared that the latter two species were being gradu- 
ally lost through hybridization with 0. demissn. 
Miss E. W. Davies. 
PoLYiu.oiDY in BBIMULA FABINOSA L. 
A tetraploid plant of Primula farinosa from the Balt'ic Island of 
Gotland ivas exhibited together with a dijdoid British plant from Tee.s- 
dale, Durham. Photographs of meiosis in the pollen mother cells were 
shown in each case. In the tetraploid n = 18 the chromosomes are 
considerably larger than tho.se of the diploid, where n = 9. 
The ))lants seem quite distinct morphologically, the tetraploid having 
rather elongated spathulate leaves with very few teeth, while those of 
the dii)loid are broader, more rounded and distinctly toothed. 
A herbarium specimen of a plant from Malhani, Yorks., which showed 
striking similarity to the Gotland tetraploid, was also exhibited. I 
