95 
[ 26 ] 
name of O. clavata' 2 most appropriate. A singular plant, with the habit 
of , a Ranunculus , but nearly related to Saurw'us, was also found in this 
neighborhood among grass on the banks of the Rio Grande. The genus 
has been described by Nuttall from specimens collected by him in Califor¬ 
nia, but whether his 'Anemopsis. californica is specifically identical with 
the new Mexican plant, remains to be seen, as this last has regularly 
6-leaved involucres, about 6 stamens, and is perfectly glabrous. 
While the last mentioned plants indicate that we approach another bo¬ 
tanical region, we are surprised to meet here with Polygonum amphibium , 
Common in the old and in the new world, and Cephalanthus occidentalism 
so widely diffused in the United States. 
' * The famous desert, the Jornada del Muerto, furnished, as was to be 
expected, its quota of interesting plants. A Crucifer a near Biscutella , of 
Europe, but with very short styles and white' flowers, was here met 
with abundantly. I had considered it as the type of a new genus, when 
I found in Hooker’s London Journal of Botany of February, 1845, Har¬ 
vey’s description of his new Californian genus Dithyrea , 13 which proba¬ 
bly must be made to embrace our plant as a second species. 
4 4 * * * * * * * 12 Opuntia clavata , n. sp. prostrata, ramulis ascendentibus, obovato- 
clavatis, tuberculatis; areolis orbiculatis albo-tomentosis, margine superiore 
setas albas spioescentes gerentibus; aculeis albis complanatisj radiantibusjd 
6-12 minoribus, centralibus 4-7 majoribus, longioribus deflexis; floribus*" 
terminalibus; areolis ovarii 30-45 albo-tomentosis, setas albas 10-15 geren¬ 
tibus ; sepalis interioribus ovptodanceplatis acuminatis s. cuspidatis; jfetalis 
obtusis, erosis saepius mucronatis; stigmatibus 7-10 brevibus erectis; bacca / 
elongato-clavata, profunde umbilicata, setaceorspinosa. 
About Albuquerque (W.,) about Santa Fe, on the high plains, never on 
the mountains, (Fendler.) Mr. Fendler informs me that the ascending 
joints sprout from or near their base, and that in this manner they finally 
form a large spreading mass, often 2. and even 4 feet in diameter, to 
which the white shining spines give a very pretty appearance. Joints or 
branchlets to 2 inches long, tubercles at their base' smaller, with 
shorter spines,* towards the upper and thicker end larger, with stouter and 
longer spines; radial spines 2 to 4, central ones from 4 to 9 or 10 lines 
long; ovary 15 lines long, flower yellow, 2 inches in diameter; stigmas 
only 1| line long;' fruit apparently dry and spiny, 1J to If inch long; 
Seeds smoother than those of most other opuntiae, rostrate, with a circular 
embryo. Apparently near Opuntiae platyacahthae, Salm.; but the tuber- 
Culated joints and the shape of the embryo approach it closely to O. cylin- 
draceae. 
ls Dithyrea, Harv., char, emendat. Sepala 4 basi aequalia oblongo- 
linearia. Petala 4 spathulata, basi ampliata. Stamina 6 tctradynama, 
libera, edentula. Stylus brevissimus, stigma incrassatum. Silicula ses- 
sili^, biscutata, basi et apice emarginata, a latere pianorcompressa. Semi¬ 
na in loculis solitaria, compressa, immarginata, horizontalia. Cotyledones 
pfanae radiculae descendenti septum spectanti accumbentes. 
Annual (all?) plants of California and New Mexico, with stellate pube¬ 
scence, repando-dentate leaves, yellow (?) or white flowers in simple 
»terminal racemes. 
Dithyrea Wislizeni , n. sp., erecta incano-pubescens ramosa, foliis brevi- 
