CACTACEA OF WHEELER’S EXPLORATION. 233 
EXPLANATION OF PLATES. 
Plate I. Echinocactus Simpsoni as it appears in early spring. On the vertex a young growth of tubercles is visible, their 
tops covered with wool. 
Plate II. Details of the same. 
Fig. 1. Four tubercles from near the vertex : one shows the broad scar where the fruit has fallen off; another one 
is just developing its —s exhibiting their points above the thick wool. 
Fig. 2. A detached tubercle beari 
Fig. 3 and 4. Flowers with the bi part of the tubercle and its young spines. 
Fig. 5 and 6. The fruit magnified three times ; fig. 5 showing the basal opening, fig. 6 the broad umbilicus. 
Fig. 7. A scale of this fruit more magnified, with two axillary spines. 
Fig. 8-12. Seed: fig. 8 natural size, the others eight times magnified ; fig. 9 lateral, fig. 10 dorsal, fig. 11 basal view; 
fig. 12 part of the surface, highly magnified. 
Fig. 13. Embryo, wists in the inner seed-coat, —_— also the at magnified. 
Fig. 14. Lateral, fig. 15 frontal view of the embryo, magni 
Fig. 16. Seedling, a few weeks old, magnified. 
Fig. 17. Tubercles of the smaller variety, from Colorado, in every state of development. 
Plate III. Fig. 1. Part of a plant of Opuntia pulchella, opie a flower-bud and two flowers, natural size. 
ig. 2-4. Bunches of spines, four times ee natura 
Fig. 5. Section of a larger spine, more magnified. 
Fig. 6. A om Si an ovary, with the eit woolly and bristly areola, four times natural size. 
Fig. 7. A fru 
Fig. 8-9. ak four times magnified ; fig. 9 showing the broad rhaphe, 
XIII. CACTACEZ OF WHEELER'S EXPLORATION. 
From bug UPON UNITED STATES gees dra SURVEYS WEST OF THE ONE HunpREDTH MERIDIAN, IN CHARGE OF 
rst LIEUTENANT George M. Wueever, U.S. Encinrrrs. Published by ENcInzeR DEPARTMENT. Vol. VI., 
Rice by J. T. Rornrock. 1878. 
MAaMILLaRIA (CoRYPHANTHA) VIVIPARA, Haw., Engelm, in Watson’s Bot. King’s Expl. 117. A common [127] 
plant on the western plains from the Missouri to Texas, extending in the mountain regions as far 
Arizona and South Utah. The large, deep rose-colored or purple flowers, with Singul sepals iat Gee 
acuminate petals, green oval berries, with light brown pitted seeds, readily distinguish the species. The form of the 
plains is lower and often densely cespitose-spreading ; the mountain plant is often simple and larger. The largest 
form, which comes from Arizona, I had at one time distinguished as M. Arizonica, but must now consider it as only 
a akin Vivipara, 3-5 inches high, 4 inches in diameter, with spines often over 1 inch long on rather broad and 
spreading tubercles, Rothrock, 1874 (203), is a smaller form, from Camp Apache, 
M. (CorYPHANTHA) CHLORANTHA, sp. nov. Similar to the last, but with fos yellow petals ; stems oval to 
cylindrical, 3 inches wide, sometimes 8-9 inches high ; tubercles compressed from above ; 20-25 outer spines gray, 
almost in 2 series ; 6-8 or 9 inner ones stouter, $-1 inch long, reddish or brownish only at the tip. Flowers yellowish 
or greenish-yellow, crowded on the top of the plant, 1} inch long and wide, often 1-2 small fringed sepals on the 
ovary (which also occasionally is seen in Vivipara) ; sepals lanceolate, fringed ; petals lanceolate or linear-lanceolate, 
acute, -denticulate; 7-9 whitish stigmas, erect-spreading. — Southern Utah, east of Saint George (Dr. Parry, 
I. E. Johnson) 
Ecutnocactus WistizENni, Engelm. Very large, often over 3 feet high and half as much in diameter 
at first globose, then ovate to cylindrical, with 21-25 5 vathod sharp ribs. The large linear-oblong areole as [128] 
oo when young) bear three kinds of spines: first, 4 very stout, annulated, reddish ones, 13-2} inches long, 
the 3 upper ones straight, the lower one hooked ; second, 3-5 lower and usually 3 up oat spines, ~ but 
straight, stiff, and annulated, of reddish color ; third, 12-20 whitish, bristle-like, flexuous, lateral spin Flowers 
2-23 inches long, 1} wide, yellow, outside greenish with purple-brown ; ovary and fruit imbricately tains with 
numerous (50-60) cordate or reniform crenulate sepals; sepals of tube oblong, ciliate ; petals broadly linear, crenate, 
bristle-pointed ; style deeply divided into 12-18 linear stigmas; seeds 1 line long or over, selieslike or ‘dullow- 
pitted. — Southern New Mexico. 
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