except that it indicates that the specimen is from plants
cultivated successfully in the gardens of Prince Salm-Dyck.

++ Flower and fruit remaining central in the very woolly vertex
of the plant.
++ Central spine solitary or wanting.

44. Cactus compactus (Engelm.) Kuntze Rev. Gen. Pl. 260 (1891).

Mamillaria compacta Engelm. Wisliz. Rep. 21 (1848).

Depressed-globose, 5 to 10 cm. in diameter, simple: tubercles
short-conical, crowded, 8 mm. long: radial spines 13 to 16,
rigid, recurved and appressed, interwoven with adjacent clusters,
whitish or horny, 10 to 20 mm. long; the erect central spine
often wanting: flowers 3 to 3.5 cm. long and broad, yellow
(brownish without): fruit oval, green: seeds 1.4 mm. long, smooth
and yellow. (Ill. Cact. Mex. Bound. t. 74. fig. 2, seeds) Type,
Wislizenus of 1846 in Herb. Mo. Bot. Gard.

Mountains of Chihuahua. Fl. June-July.

Specimens examined: Chihuahua (Wislizenus of 1846): also
specimens cultivated in St. Louis in 1848, 1850, 1854.

45. Cactus radians. (DC.) Kuntze, Rev. Gen. Pl. 261 (1891).

Mamillaria radians DC. Rev. Cact. 111 (1829).
Mamillaria pectinata Engelm Syn. Cact. 266 (1856).