ECHINOCACTUS. 167 
about a dozen species of this relationship which have been described; to these we append 
3 species of the southwestern United States and border states of northern Mexico, one 
with smooth, the others with papillose seeds. 
Echinocactus texensis has a similar woolly ovary, but the fruit is fleshy, with different 
seeds and purple flowers; this we regard as a new generic type. 
Astrophytum with its 4 species, usually classed as Echinocactus, also has pubescent 
fruit, but is very different in other respects. 
There are 2 other cacti from North America which bear wool on the ovary, E. whipplei 
and FE. polyancistrus. ‘These have only small scales on the ovary, bearing minute tufts of 
hairs in their axils and have very different seeds. We refer them to a new genus (see p. 
212). 
In South America there are 2 old genera with woolly fruit which have been associated 
with Echinocactus, namely, Malacocarpus and Eriosyce, both of which, in our opinion, are 
generically distinct. 
KEy TO SPECIES. 
A. Plants very large, often becoming cylindric (see No. 5). 
Spines all bright yellow......... 
wee eee eee eect ee ee eee eees .. 1. E. grusonii 
Spines brown to gray, rarely some of them yellowish. 
Inner perianth-segments linear-oblong, entire.....:......................... 2. E, ingens 
Inner perianth-segments oblong, more or less toothed or lacerate. ; 
Spines all of one kind...... cece eee ee cece ee teeteeeeesseeesess 3. E, visnaga 
Spines both radial and central. 
Central spine solitary. 
Flowers 4 to 5 cm. long; central spine 4 to 5 cm. long, nearly black. 4. E. grandis 
Flowers 3 cm. long; central spine 3 cm. long, grayish in age...... 5. E. platyacanthus 
AA Central spines several....... 0000000 ce cee ce eee eee eee ees. 6 E. palmeri 
. Plants relatively small, subglobose. . 
Seeds smooth and shining. ..... 0.00... 06.0 ee eee ve ee ee eee ee ee ee en seeneeees 7. E. xeranthemoides 
eds papillose. 
bee ceceeseseesesere... 8 E. polycephalus 
Flowers ga Ss E  eathalonins 
? 
1. Echinocactus grusonii Hildmann, Monatsschr. Kakteenk. 1:4. 1891. 
Plants single, depressed-globose, large, 2 to 13 dm. high or more, often 4 to 8 dm. in diameter, 
light green; ribs 21 to 37, rather thin and high; spines when young golden yellow, becoming pale and 
nearly white, but in age dirty brown; radial spines 8 to 10, subulate, 3 cm. long; central spines us any 
4, up to 5 cm. long; flowers 4 to 6 cm. long, opening in bright sunlight, 5 cm. brea a op, the seg 
ments never widely spreading; flower-tube 3 cm. broad, covered with lanceolate, jong ac minate 
scales; outer perianth-segments long-acuminate, brownish on the outside, yellowish wi in; inner 
perianth-segments cadmium-yellow, with a silky luster, erect, narrowly lanceolate, ge eae a 
shorter than the outer segments; stamens numerous, yellow, connivent, commie a ane bode der in 
the center of the perianth; style yellow; stigma-lobes 12; ovary spherical, aring a a eciied 
with an abundance of wool in their axils; fruit oblong to spherical, 12 to 20 mm. long, th unin 
covered with white wool or becoming naked below; seeds smooth, dark chestnut-brown, 
1.5 mm. long. 
Type locality: Central Mexico. daleo, Mexi 
Distribution: San Luis Potosi to Hidalgo, exICO. ; 
This is a very attractive species and is much grown in collections, but usually only small 
plants are seen. . 7 
We are greatly indebted to Mr. E. C. Rost, a private grower of cacti in southern Cale 
fornia and a very keen observer, not only for procuring for us flower fruits, an + ny 
Photographs, but also for valuable observations. He writes that . i i . * v hich the 
imbedded in the dense felt cushion and must actually be dug out. . ¢ Phe dowers oper 
flowers are sunk is shown by a definite band near the top of the ovary 7 The ctanens 
in sun-light and the perianth-segments are nearly erect or slightly sprea tn following ve 
and style are erect. Under date of October 9, 1919, Mr. Rost sent us 
ment regarding this plant: 
