1a. Sagina nodosa (Linnaeus) Fenzl subsp. nodosa
Sagina nodosa var. pubescens (Besser) Koch
Stems glandular-pubescent. Basal leaf blades glandular-pubescent, especially on margins and midrib, or glabrous. Pedicels glandular-pubescent distally. Flowers: calyx base glandular-pubescent. 2n = 56.
Flowering mid-late summer. Coastal, moist crevices of rocks along seashore and on sea cliffs, wet sand flats at river mouths; 0-300 m; introduced; St. Pierre and Miquelon; N.B., Nfld. and Labr. (Nfld.), N.S.; Maine, Mass., N.H.; Europe.
Subspecies nodosa is probably introduced in North America. Its localities tend to be correlated with coastal regions that had an early history of fishing by Europeans; it may have been introduced with the dumping of ballast. It was collected at least once from New Hampshire where it apparently has been extirpated.
Some variation occurs in the amount and distribution of pubescence on the leaf surface in subsp. nodosa. In plants with a lesser amount of pubescence, the glandular hairs are restricted chiefly to the leaf margins; the leaves may even be glabrous. This seems to be the case primarily when subsp. nodosa and the native subsp. borealis occur in the same vicinity, such as some populations along the Saint Lawrence Seaway, Grand Manan Islands, New Brunswick, and Machaias, Maine. More typically, the plants are pubescent and the trichomes are more frequent along the veins on the abaxial surface as well as the leaf margins.