This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this species is copses and rocks, chiefly near the sea, stony places in S. and W. England. The habit is erect or spreading. The plant is smooth, shining, except for the recurved prickles on the stem angles, midrib, and leaf margins. The old stem is round, the shoots square, spreading. The leaves are in whorls of 4-6, elliptic, oblong, lance-shaped, smooth above, nerveless, the margin and keel having turned-back bristles, rigid, and evergreen. The flowers are in axillary or terminal, panicled cymes, longer than the leaves, greenish-yellow. The lobes of the 5-cleft, wheel-shaped corolla are spreading, oval, narrowed to a fine point. The stamens are short, the 2 styles united below, the stigmas pinheaded. The fruit is black, small, rounded. Madder is 1-2 ft. high. The flowers appear from June to August. The plant is a herbaceous perennial.
Asperula taurina, L - This plant is an alien found in shrubberies. The habit is erect. The leaves are 4 in a whorl, elliptic, with a long, narrow point, 3-veined. The flowers are pinkish-white in a corymb, the tube of the corolla very long, the fruit rather rough. The plant is 6-28 in. in height, and flowers in May and June, being a herbaceous perennial.