GEYER’S PLANTS OF ILLINOIS AND MISSOURL 509 
species in the formation of hybrids, sia spikes are filiform, the flowers compacter than in V. urticefolia, but [101] 
not as densely imbricated as in V. stricta or V. paniculata ; the calyx much longer than in V. urticefolia, canes- 
cently hairy ; corolla large, bi Sesionations 4 in size between both parents, and pale purple. This is the most abundant 
hybrid here, and both parents are amongst the most common weeds about St. Louis. Flowers in J uly and August. 
102. URTICHFOLIO-PANICULATA: leaves petioled, lanceolate, with simple, double, or sometimes incised serra- 
tures, generally elongated ; spikes thin, more properly filiform than in any of our species ; calyx and corolla interme- 
diate in shape, size, and color, between both parents. It resembles some varieties of the true V. paniculata, but the 
dark purple flowers and the thick pera tre fruiting spikes at once distinguish it. St. Louis and Beardstown; grassy 
places and open woods. July and August. 
sides these four hybrids, I have found here the a. ones more nearly resembling the other parent, 
which I designate by the same names, reversing the order, 
. STRICTO-PANICULATA : greener, narrower, more panies leaves, darker flowers, than V. paniculato-stricta. 
V. BRACTEOSO-URTICZFOLIA : adscendent, with large lobed leaves, and thinner spikes. 
V. URTICHFOLIO-STRICTA : canescent, with sessile lonves, and thin filiform spikes. 
V. PANICULATO-URTICZFOLIA : with broader leaves, thinner spikes, paler and smaller flowers. 
Then there is the V. angustifolio-stricta and V. stricto-angustifolia. Hybrids of V. angustifolia with any but V. 
stricta, and of V. bracteosa with any but V. urticefolia, or of V. Aubletia, the only remaining species in this region, I 
have not yet found. The only other hybrid found by me in this country is Rumex obtusifolio-crispus. Whether these 
alec oa plants hybridize in their native country is unknown to me. 
103. ANDROSACE OCCIDENTALIS, Pursh. 104. Lystmacuia revotuTa, Nutt. 105. Praxtaco corpata, Lam. 
106. Potyconum TeNvE, Michz. 107. P. sacitratum, Linn. Croton GLANDULOsUs, Linn. 109. Borya 
LicustrRiIna, Willd. 110. Quercus wiera, Willd. 111. Q. aupa, Linn. 112. Q. castanea, Muhl. 113. Satrx [102] 
Movutensperorana, Willd. 114. 8. nicra, Marsh. 115. 8. toneirotia, Muhl. 116. S. n1erpa, Muhl. ? 
117. Poramocerton Diverstroius, Barton, 8. spicatus. This form appears at first view to be a distinct species, 
characterized by the narrower, only 5-nerved upper leaves, and petioled oval or cylindric spikes. P. diversifolius, a. 
capitatus, the common form, has more oval 7-nerved upper leaves, and nearly sessile few-flowered heads. But some- 
times the lower heads of our variety are also capitate and nearly sessile, and the fruit is generally alike. The fruit, or 
nut, is always compressed, winged on the back, with two lateral carine, which are generally denticulate, the nut 
appearing muricate; and in 8. they are often cated or entirely undivided, but by no means genera he 
embryo describes 1} spiral circumvolution; the em of mo st oe) species forms only 3, 1, or 1} circumvolation. 
I know but one species, P. densus, which exhibits 23 cireumvolut 
It may not be amiss here to remind botanists in this eer Cut the ripe fruit furnishes the best characteristic 
marks to distinguish the different species of Potumogeton. The fruit, for example, proves that P. marinus, Linn., 
entirely distinct from P. pectinatus, Linn., with which most authors confound it; P. marinus occurs not only on the 
sea-coast, but also in the salt-ponds of the Upper Missouri (Geyer, in Nicollet’s Expedition). cs coemanse ot Potamo- 
geton peas ie be collected with ripe fruit. 
. PHALANGIUM ESCULENTUM, Nutt. 119. Trru10m recurvatum, Beck. 120. Juncus mMarerNatus, Rostk. 
121, Batis SPATHACEUM, Pers, 122. CypERUS KYLLINGXOIDES, Vahl. 123. IsoLepis caPILLaRIs, Rim. & Schult 
124. seen TENUIS, Schult. 
125. Extopnorum Gracite, Koch, in Roth. Catalect. 2, p. 259. A species which has frequently been found in 
the United ma it appears to have been taken for FZ. angustifolium — my a prime at least, received from Penn- 
sylvania and from Ohio, were so labelled — but is easily distinguished by past subulate Jeaves, and the 
linear yellowish seeds. The true £. ain oI Roth., is the largest of ‘al e species, with the longest 
(1k inch) wool; leaves 1 or 1} lines broad, channelled ; peduncles sesootli: E. shel sah Hoppe (£. polystachyum, [103] 
Auct.), has flat leaves and scabrous peduncles ; oad both have obovate, dark or light brown seeds. 
ropose the following disposition of these species, acknowledging, however, that I have studied the American 
varieties from dried specimens only, never having observed any living ones: 
E. tatirotrum, Hoppe: culmo yn foliis planis apice triquetris, apioulie plurimis, pedunculis scabris, nuci- 
bus pet eaess E. polystachyum, B., L 
IGRO-CARINATUM: squamis florifers plumbeis, carina nigricante, nucibus acutiusculis brunneis. Germany; 
er oty aeesiecet Euro 
. VIRIDI-CARINATUM: eqammnis floriferis obscuris, carina virescente, nucibus obtusis, Intescentibus. Massachu- 
setts, Ohio, 
ANGusSTIFOLIUM, Roth.: eulmo . eee foliis canaliculatis apice triquetris, spiculis pluribus, pedunculis 
laviben, nucibus oblanceolatis acutis. E. polyst achyum, a., Linn. Squame florifere nigro-carinate, albo-marginate. 
Europe. : _ not seen any American specimens. 
E. eraciiz, Koch ; culmo shanigls trigono, foliis triqnetris, spiculis pluribus, pedunculis scabris, nucibus lineari- 
bus ‘heeehsecaSbna}: E. polystachyum, y., Linn. E. triquetrwm, Hoppe. 
