Mamillaria chlorantha Engelm. Wheeler's Rep. 127 (1878).
Oval to cylindrical (7.5 cm. in diameter, sometimes 20 to 22.5
cm. high), with 20 to 25 gray radial spines almost in two series,
6 to 9 stouter reddish or brownish-tipped centrals (12 to 25 mm.
long), and yellowish or greenish-yellow flowers 3.5 cm. long and
wide. Type: Southern Utah specimens of both Parry and Johnson
occur in Herb. Mo. Bot. Gard., but they are all referred to C.
radiosus arizonicus, and I can find no trace of any specimens of
C. radiosus chloranthus in the Engelmann collection.
Southern Utah, east of St. George (Parry; Johnson).
The plant is evidently near C. radiosus deserti, of which variety
it seems to be the Utah representative, but in the absence not
only of the type, but even of authentic specimens, the two are
kept separate, a thing fully justified by the description.