Spring Flora of Oklahoma 
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!• Spermolepis divaricatus (Walt.) Britton. Rough-fruited 
Spermolepis. Very slender and widely branching. Rays of the 
umbels almost filiform, divaricate. Flowers about broad. Pedi¬ 
cels filiform, 3"-6" long. Fruit ovate, densely tuberculate, 6" long. 
In sandy soil and on prairies. April-May. Frequent. 
2. Spermolepis patens (Nutt.) Robinson. Spreading Spermo- 
lepsis. Erect, slender, 12'-24' high. Stem-leaves short-petioled, bi- 
ternately dissected into narrowly linear, filiform segments. Umbels 
terminal, or axillary, 6"-18" broad. Rays 3"-6" long. Pedicels 
1MST-2T long in full fruit. Fruit ovate, slightly more than long, 
more or less tuberculate. 
Sandy soil, May-June. Frequent. 
VII. AMMOSEUNUM T. & G. 
Annual, caulescent, diffuse herbs. Leaves alternate, ter- 
nately dissected. Flowers perfect in compound umbels. In¬ 
volucres and involucels of several entire or dissected bracts. 
Disk with a short, conic stylopodium. Fruit longer than 
broad. Carpels terete or slightly laterally flattened, with 
5 prominent ribs which are tuberculate or spiny. Oil-tubes 
solitary in the intervals and 2 in the inner side. 
1. Ammoselinum Popei T. & G. Pope’s Sand-Parsley. Dif¬ 
fuse, 6'-15' high, rough. Lower leaves slender-petioled, the upper 
sessile, all dissected into linear segments about wide. Fruit 
ovate, 2"-2%" long, narrowed above, 1" wide or a little more, the 
ribs rather strongly tuberculate. 
In sandy soil. April-May. Oklahoma County. 
VIII. PTILIMNIUM Raf. 
Annual, caulescent herbs. Leaves alternate, pinnately, 
or ternately dissected into narrow or filiform segments, 
and compound umbels of white flowers. Involucres and 
involucels of several slender, often dissected, bracts. Styl¬ 
opodium conic. Fruit slightly flattened, glabrous. Car¬ 
pels dorsally compressed, the dorsal and intermediate ribs 
prominent, slender, the lateral ones very thick and corky. 
Oil-tubes solitary in the intervals. Seed-face flat. 
1. Ptilimnium Nuttallii (DC) Britton. Nuttall’s Mock Bishop 
Weed. Stem erect or ascending, 24'-36' high, branching above. Leaf- 
blades finely dissected, the segments filiform. Fruit nearly orbicular, 
y 2 " long. 
In swamps. May-September. Central part of state. 
