Crossword-Solution: PISUM 5 letters, 1 clue 🏆 scrabble score: 9

Darwin showed that Pisum sativum and Lathyrus odoratus belong to plants in which self-pollination is regularly effected, and that this accounts for the constancy of certain sorts of these plants, while a variety of form is produced by crossing.

Similar forms were found in Mimulus luteus and Nicotiana (In Pisum sativum also the crossing of two individuals of the same variety produced no advantage; Darwin attributed this to the fact that the plants had for several generations been self-fertilised and in each generation cultivated under almost the same conditions.

The best evidence, however, that the twisting does not cause the revolving movement is afforded by many leaf-climbing and tendril-bearing plants (as _Pisum sativum_, _Echinocystis lobata_, _Bignonia capreolata_, _Eccremocarpus scaber_, and with the leaf-climbers, _Solanum jasminoides_ and various species of _Clematis_), of which the internodes are not twisted, but which, as we shall hereafter see, regularly perform revolving movements like those of true twining-plants.

See "Variation under Domestication," Edition II., Volume II., page 68; but the explanation there given for Pisum may probably apply to Lathyrus.), bee-orchis, and perhaps hollyhocks are, at present, my greatest difficulties; and I find I cannot experimentise by castrating sweet-peas, without doing fatal injury.

Among other characteristic shells are _Pecten Hœninghausii,_ and a species of _ Cassidaria,_ and several of the genus _Pleurotoma._ Not a few of these testacea agree with English Eocene species, such as _Actæon simulatus,_ Sowb, _Cancellaria evulsa,_ Brander, _Corbula pisum_ (Fig.