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ZF 
42 THE CACTACEAE. 
Echinocactus radiatus Hortus Belg. was referred as a synonym of Mammillaria 
pycnacantha by Pfeiffer (Enum. Cact. 180. 1837). 
Illustrations: Nov. Act. Nat. Cur. 16: pl. 17; Loudon, Encycl. Pl. ed. 3. 1379. f. 19387; 
Abh. Bayer. Akad. Wiss. Miinchen 2: pl. 3; Pfeiffer and Otto, Abbild. Beschr. Cact. 1: 
pl. 26; Curtis’s Bot. Mag. 69: pl. 3972, as Mammillaria pycnacantha. 
Figure 39 is reproduced from the first illustration cited above; a spine-cluster is also 
shown. 
28. Coryphantha echinus (Engelmann). 
Mammillaria echinus Engelmann, Proc. Amer. Acad. 3: 267. 1856. 
Cactus echinus Kuntze, Rev. Gen. Pl. 1: 260. 1891. 
Mammillaria radians echinus Schumann, Gesamtb. Kakteen 496. 1898. 
Solitary, globose to subconic, 3 to 5 cm. in diameter, almost hidden under the closely appressed 
spines; areoles orbicular or a little longer than broad; radial spines numerous, white, 10 to 16 mm. 
long; central spines 3 or 4, the 3 upper erect or connivent over the apex, the lower one porrect on 
side of plant, erect near top, subulate, straight, 1.5 to 2.5 cm. long, often blackish; flowers 2.5 to 
5 cm. long, yellow; outer perianth-segments linear-lanceolate; inner perianth-segments 20 to 30, 
narrow; stigma-lobes about 12; fruit oblong, 12 mm. long. 
Type locality: On the Pecos River, Texas. 
Distribution: Western Texas. 
The flowers with the type plant seem to have been shriveled, for Engelmann describes 
them as large, apparently about 11% or 2 inches long; in a later description he states that 
they are yellow. This species is very rare in collections and we have seen no flowers of it. 
All the illustrations cited below are based on the figure in the Mexican Boundary Survey. 
The name Coryphantha echinus occurs in C. R. Orcutt’s Circular to Cactus Fanciers, 
1922. 
Illustrations: Cact. Mex. Bound. pl. 10; Dict. Gard. Nicholson 4: 562. f. 32; Suppl. 
515. f. 549; Watson, Cact. Cult. 157. f. 59; ed. 3. f. 37; Forster, Handb. Cact. ed. 2. 404. f. 
43; Blanc, Cacti 68. f. 1228, as Mammillaria echinus ; Schelle, Handb. Kakteenk. 240. f. 159, ° 
as M. radians echinus. 
Figure 310 is from a photograph of a plant obtained by George L. Fisher near Langtry, 
Texas, in 1922. 
—— 29. Coryphantha durangensis (Riinge). 
—_ Mammillaria durangensis Riinge in Schumann, Gesamtb. Kakteen 478. 1808. 
Plants solitary or in small clusters, short-cylindric, 10 cm. long or less, somewhat glaucous; 
tubercles rather prominent, in 5 or 8 series, somewhat compressed dorsally, very woolly in the axils; 
radial spines 6 to 8, acicular, spreading, 1 cm. long or less; central spine solitary, often erect, those 
of uppermost areoles connivent, black; flowers very small, about 2 cm. long, when fully expanded 
2.5 to 4 cm. broad; outer perianth-segments dark purple or with only a purple stripe down center; 
inner perianth-segments cream-colored to pale lemon-yellow; filaments cream-colored, about length 
of style; style and stigma-lobes cream-colored, the latter 5, linear and curved backward; fruit globu- 
lar, 5 to 8 mm. in diameter, naked, greenish; seeds brown, about 1 mm. broad. 
Type locality: Villa Lerdo, Durango, Mexico. 
Distribution: Northern Mexico. 
Dr. E. Chaffey has collected this plant for us several times at the type locality, but it 
does not survive long under glass. In 1911 he found a cristate form with the lobes flat- 
tened like the joints of an Opuntia, bearing flowers along the edges. 
This is Mammillaria compressa of Hildmann’s Catalogue, according to Schumann 
(Gesamtb. Kakteen 479. 1898). 
Illustration: Wiener Ill. Gart. Zeit. 29: 411. f. 105, as Mammillaria radians. 
_ Plate v, figure 4, shows a plant sent by Dr. Chaffey from the type locality in 1918, 
which flowered in the New York Botanical Garden, April 8, 1918. Figure 40 is from a 
photograph of a potted plant sent by Dr. Chaffey in 1910 which flowered in Washington ; 
figure 41 is froma photograph of another plant sent by Dr. Chaffey in 1910. 
