Apr., 1921J 
TRELEASE — NORTH AMERICAN PIPERS 
213 
statement made earlier, that however simply a section may be conceived, 
in Piper, it is certain to prove heterogeneous in what are regarded ordinarily 
as significant floral characters. 
As here construed, excluding the Javan Piper Zippelia, the Ottonias 
are exclusively American. Two thirds of their number occur in South 
America; and one appears to be limited to the continental island Trinidad. 
Of the others, eight are Mexican: one in the lowlands of Yucatan, two in 
the Eastern Sierra Madre and Cordillera, and five in the Western Sierra 
Madre. One species is Honduranian, and one Nicaraguan. 
Except for the Trinidad species, which, like those of continental South 
America, has pinnately veined leaves, all of these have palmately nerved 
foliage. In contrast with those of the eastern slope, which have elongated, 
rather lance-ovate leaves, those of western Mexico bear round-ovate, 
often shallowly cordate-truncate leaves. 
In the diagnostic stalking of their flowers they present a gradation from 
the close-set, nearly sessile flowers of P. brachypiis to those with a pedicel 
distinctly longer than the flower. 
Characteristically hypogynous, the stamens in two species are adnate 
to the ovary for a considerable distance; in this respect paralleling the 
sessile-flowered Pipers, some of which are quite hypogynous while others 
have epigynous stamens. In one of the Ottonias, P. abalienatum, the 
stamens form two separated alternating whorls around the ovary. 
Though the stigmas are essentially sessile on the ovary in species like 
P. Muelleri and the epigynous P. alhicaule, the fruiting ovary is attenuate 
into something of a beak in the former; and P. abalienatum, even when in 
flower, possesses a columnar style essentially as long as the ovary. Perhaps 
the most interesting species in this respect is P. brachypus, in which a very 
short, thick style matures into a stylopodial disk which caps the fruit and 
is comparable with that of the sessile-flowered P. smilacifolium — one form 
of which was segregated formerly under the name P. discophomm. 
Conspectus of the North American Ottonias 
Leaves pinnately nerved. 
Piper ovatum. 
Leaves palmately nerved. 
Leaves distinctly longer than broad. 
Leaves somewhat pubescent beneath. 
Leaves and petioles glabrous or barely puberulous. 
P. Muelleri. 
Leaves broadly ovate. 
P. yucatanense. 
Leaves lance-ovate: spikes rather short. 
Leaves acute and minutely subauriculate at base. 
P. Neesianum. 
Leaves rounded at base. 
Spikes scarcely 20 mm. long. 
Spikes 25-30 mm. long. 
P. Thiemeanum. 
P. Tatei. 
Leaves about as broad as long. 
Pedicels very short. 
Pedicels very evident. 
P. brachypus. 
