Upright cells, however, are more common in rays of such species as Cheiranthus mutabilis and Stanleya pinnata (Fig.
Within Brassicaceae, the longest vessel element lengths occur in the species with the most mesic habitat, Cheiranthus mutabilis, from Madeiran laurel forest openings (Carlquist, 1971).
Botanically, they are now Erysimum, a term of obscure origin, but their former name, Cheiranthus
, translated from Greek as hand-flower, is thought to refer to their popularity ( long before the 20th Century ( as posies carried in the hand where their sweet scent could be appreciated.
The taxonomists have now put cheiranthus
and erysimum in the same genus and so they are all called erysimum nowadays.
Perennials that deliver lots of showy blooms in spring and summer without copious amounts of water include bougainvillea 'Crimson Jewel', gaillardia (pictured at left), erysimum (also sold as Cheiranthus
'Mauve clusters'), lavender, garden penstemon, salvia superba 'East Friesland', and yarrow.
Polyanthus and wallflowers are reliable as are winter flowering pansies while the Siberian wallflower, cheiranthus
, is useful as you can cut it back hard after flowering and it will bloom again in summer.
He originally ascribed the preferential production of outcrossed progeny in Cheiranthus to differential pollen-tube growth in the style, but selective abortion of selfed seeds caused by inbreeding depression also increases the frequency of outcrossing in self-compatible species (Moran and Brown 1980; Levin 1984; Cheliak et al.
Cryptic incompatibility has been reported in both nonheterostylous (Cheiranthus cheiri, Bateman 1956; Clarkia unguiculata, Bowman 1987; also see Ockendon and Currah 1978) and heterostylous species (Amsinckia grandiflora, Weller and Ornduff 1977, 1989, 1991; A.