Subularia.] VI. CRUCIFERE. | 43 
and pointed, 4 tol inch long. Flowers few, with minute white petals. 
Pods about a line and a half long, and oblong, or sometimes shorter, 
and nearly globular, with 5 or 6 seeds in each cell. 
In the shallow edges of alpine ponds and lakes, in northern Europe, 
Asia, and America, and more rarely in central Europe. Scarce in 
‘Britain, in the mountains of Scotland, north-western England, North 
Wales, and western Ireland. 1. summer. 
XVII. THLASPI. PENNYCRESS. 
Annuals or low perennials, the leaves usually undivided, the upper 
ones clasping the stem, the flowers small and white. Petals equal, or 
nearly so. Pod orbicular or obovate, flattened laterally at right angles 
to the narrow partition, the valves boat-shaped, their midrib or keel 
more or less expanded into a green wing surrounding the pod. Seeds 
2 or more in each cell. Radicle accumbent. 
A small genus, spread over Europe, northern and central Asia, and 
North America, distinguished from /beris and Lepidiwm by having more 
than 1 seed in each cell of the pod, from all others by the winged 
pod, 
Pod (including the broad wing) orbicular, about 6 lines broad . 1. 7. arvense. 
Pod obovate or obcordate, not 3 lines broad. 
Biennial or perennial. Pod longer than broad, with 6 or 8 seeds 
in each cell 
Annual. Pod nearly as broad as Tong, with about 4 seeds in 
each cell : 
2 
T. alpestre. 
i~) 
. T. perfoliatum. 
1. T. arvense, Linn. ig. 96). Mithridate aie, —An erect, glab- 
‘rous annual, 6 inches to a foot high or rather more, simple or branched 
inthe upper part. Radicalleaves stalked, but soon disappearing. Stem- 
leaves oblong or lanceolate, usually marked with a few coarse teeth; 
the lower ones narrowed at the base, the upper clasping the stem with 
prominent auricles. Pods in.a long raceme, about half an inch in 
diameter, including a very broad wing, deeply notched at the top, with 
a very minute style in the notch. Seeds usually 6 in each cell. 
In cultivated and waste places, throughout Europe and Russian Asia 
to N.W. India. Widely scattered over various parts of Britain, but not 
so common with us as on the Continent. 1. spring and summer. 
2. T. perfoliatum, Linn. (fig.97). Perfoliate P.—A glabrous annual, 
branching at the base, or nearly simple, the stem ascending or erect, 
3 to 6inches high. Radical leaves spreading or tufted, stalked, ovate 
or orbicular ; upper stem-leaves ovate or oblong, clasping the stem with 
rather large rounded auricles. Pods not half the size of those of 7’. 
arvense, With narrower wings, and the notch much broader and more 
open. Style nearly as long, or longer than the notch. Seeds usually 
4 in each cell. 
In stony pastures and waste places, chiefly in limestone districts, in 
central and southern Europe, and temperate Asia. In Britain: appa- 
rently confined to a few localities in E. Gloucestershire. Fl. spring. 
3. T. alpestre, Linn. (fig. 98). Alpine P.—A glabrous biennial or 
perennial, forming a shortly branched or tufted stock, with obovate 
oval or oblong, stalked, radical leaves. Stems simple, erect or ascend- 
ing, about 6 inches high; the leaves narrow, clasping the stem with 
