STATISTICS OF THE ORDER CRUCIFERA. 401 
shrubby yellow Wallflower of the old castle or ancient brick wall 
may be gathered in season a month later than the more showy 
garden one. Hutchinsia petrea and Teesdalia nudicaulis flower 
early; the former in March and April, the latter in April and 
May. Jsatis tinctoria, a very local species, flowers in May, or 
even earlier (on the débris of chalk-pits at Guildford). By far 
the largest portion of the Crucifere flowers about midsummer, or 
some time in the month of June. The Barbareas, Dame’s Violet, 
and Toothwort, Rape, Cochlearia danica, Thlaspi arvense, and T. 
perfoliatum are rather earlier than June, but in this month they 
will be found in a state fit for examination or preservation. At 
midsummer few indeed of the Crucifere are past flowering. 
Hutchinsia, on the bare, exposed wall at Eltham, in Kent, where 
it has long grown, is dried up or perhaps quite invisible at mid- 
summer; but we believe that at Malham Tarn, in Yorkshire, 
some plants at least of this early species will be seen m a fresh or 
growing state as late as midsummer. The Watercress remains in 
flower long after midsummer, and the yellow-flowered species of 
Nasturtium till September, or even later. Turritis, Arabis, all 
the species except A. stricta, which is early, Sisymbrium, all ex- 
cept thalianum and Alliaria, Erysimum, Brassica, and Sinapis are 
in flower from midsummer to Lammas. The rarer species, Diplo- 
taxis tenuifolia, D. muralis, and Sinapis monensis, are rather later 
than the former-noticed species. The Scurvy-grass, Drabas, with 
the exception of the early species already mentioned, are in flower 
during the whole summer, but they begin to disappear in August. 
The Lepidia flower all summer, and rarely before June. Swine’s- 
cress, Senebiera, and Wild Radish will be found at the same 
season. In June, the first of our summer months, all the Cruci- 
fere but the very early flowerers may be collected in flower, 
and in July most of them in fruit also. In August it will not be 
too late to look for the majority of this Order ; they are plentiful 
even in September, and in October several are still in fruit and 
im flower also. 
The duration of the Cruciferous species varies from a few 
months, or perhaps weeks, to many years. The terms annual, 
biennial, and perennial, as they are generally applied to vegeta- 
tion, are not very definite. Species usually termed annual do not 
always endure for a year, and they sometimes, nay often, exist 
during a portion of two years. Some biennials, under certain laws, 
N.S. VOL. I. aoe 
