ENGELMANN—ADD. TO CACTUS-ELORA OF U. S. 201 
diameter, pale yellow; ovary 8-9 1. long, with 13-15 areolae, 
densely covered with white wool, the upper ones with a few 
w r hite spines ; lower sepals broadly oval, with a short cusp ; 
petals 5 obovate, roundish, crenulate; style longer than sta¬ 
mens; stigmas 5, short, cuspidate, erect. 
11. Optotia pflchella, spec. nov.: parvula, diffusa; arti- 
culis obovato-clavatis leviter tuberculatis; foliis minutis e 
basi ovata subulatis; ■ areolis cOnfertis, superioribus aculeos 
albidos rectos, singulum longiorem complanatum porrectum 
seu deflexum, cseteros brevissimos radiantes gerentibus; 
floris purpurei ovario areolis 13-15 albo-villosissimis et acule- 
oligeris dense stipato; sepalis inferioribus lineari-oblongis 
breviter cuspid a'tis, superioribus cuneato-spatulatis; petalis 8 
obovatis obtusis; stylo cylindrico exserto, stigmatibus 5 line- 
aribus suberectis. 
Sandy deserts on Walker River, Nevada; fl. in June. 
This is one of the smallest and prettiest species of the genus 
and belongs to the section Clavatce (Syn. Cact., p. 46); 
it is readily distinguished from its allies by the small joints 
and purple flowers. Joints 1-1£ inches long; leaves scarcely 
1 line long; flower bright purplish red or deep rose red, 
H-li inches in diameter; ovary 4-5 1. long, beset with white 
bristly spines, 15-25 on each areola; style not ventricose in 
the lower half, as is usual. in this genus ;* stigmas slender, 
pale yellow. 
From other sources I am enabled to give the following fur* 
ther Additions and Corrections to my former publications : 
Many JEumamillarice (Syn. Cact., p. 4) have an “ ovarium 
exsertum /” not only the large flowered Loyigimammce, which 
approach closely to Corypantha, deviate in this respect from 
the assumed character of the subgenus, but in a great many 
other species I find the same peculiarity; so that I am in¬ 
clined to restrict the ovarium immersum to that natural sub¬ 
division, the Lactescentes , already recognized by Zuccarini; 
probably all those with limpid juice harve an exsert ovary. 
Mamillaria barbata , Eng. This species is easily propa¬ 
gated by seed, and is apt to flower already in the second year. 
The first flowers in spring (May) appear in the axils of the 
last, innermost tubercles of the last year, and are, therefore, 
almost central; the later ones seem to be developed from the 
axils of the first tubercles of the same spring ! Flowers 9-10 
1. long, of the same diameter; tube constricted above the ex* 
sert oval ovary; 12-13 exterior green sepals, lanceolate, cus¬ 
pidate, fimbriate, 8 interior ones, reddish, longer, lance-linear, 
* Another deviation from the usual form I observe in the style of 
O. coccionellifera; from a very narrow and short base it is suddenly di¬ 
lated 5 or 6 times its diameter, and then gradually contracts upwards. 
