238 CUCUEBITACE^E. Petalonyx. 



'toothed, the upper sessile, the lower on rather short petioles : flowers large, on 

 pedicels 3 to C lines long, in terminal bracteate cymes : calyx-lobes lanceolate, 6 to 

 1 lines long ; petals twice longer, broadly spatulate, abruptly acuminate, hairy at 

 the apex, united at base into a tube 3 lines long : filaments equalling the calyx- 

 lobes : style stout, cleft to the middle : capsule broadly obovoid, half an inch long, 

 opening by 5 erect valves as in the other species; the seeds also exceedingly numer- 

 ous, linear-oblong, about a fifth of a line long, marked by a few longitudinal stria;. 

 — Am. Naturalist, ix. 144. Mentzelia urens, Gray, Proc. Am. Acad. x. 71, Am. 

 Naturalist, ix. 271. 



Collected b}' Bigelow in rocky arroyos near the confluence of the Williams River with tie Colo- 

 rado, and eastward to Southern Utah, Parry. 



3. PETALONYX, Gray. 



Calyx-tube very small, cylindrical, with 5 linear deciduous lobes as long as the 

 ovary. Petals 5, with long connivent claws and ovate-spatulate blade. Stamens 5, 

 with free filiform filaments, inserted with the petals on the outer edge of an epigy- 

 nous disk ; anthers small, didymous. Ovary 1-celled : style simple, elongated : 

 stigma entire : ovule solitary, pendulous from the summit of the cell. Capsule very 

 small, oblong, bursting irregularly. Seed oblong, smooth. — Erect perennial herbs, 

 or shrubby at base, pubescent or rough with short barbed hairs; leaves alternate, 

 entire or toothed ; flowers small, yellowish, in terminal heads or short leafy spikes. 

 Three species, of Arizona and the adjacent region. 



1. P. Thurberi, Gray. Stems 1 to 2 feet high from a somewhat woody base, 

 branching : leaves ovate to oblong, an inch long or less, smaller and becoming bract- 

 like (2 to 3 lines long) on the- branches, sessile, acute, entire or rarely few-toothed ; 

 the floral bracts ovate, acuminate, toothed at base : flowers in short and dense 

 spikes, sessile : calyx 2 lines long : petals light yellow, 2 lines long or more, slightly 

 hispid : filaments and style half an inch long : capsule a line long, not angled or 

 winged. —PI. Thurb. 319 ; Torrey, Bot. Mex. Bound, t. 22. 



San Diego and San Bernardino counties, and adjacent parts of Arizona to S. Nevada, Thur- 

 bcr, Cooper, Schott, Palmer, &c. 



P. nitidus, Watson, is found in S. Nevada and probably extends into S. E. California ; dis- 

 tinguished by its ovate petioled coarsely toothed leaves, rounded at base, not greatly reduced on 

 the branches, and with a somewhat vitreous and shining surface. 



P. Parryi, Gray, is a more eastern species, of S. Utah, decidedly shrubby, the leaves rhom- 

 boidal-ovate, cuneate into a short petioley scarcely smaller above. 



Order XLI. CUCURBITACE.2E. 



Herbs, mostly tendril-bearing and climbing, rather succulent, with alternate and 

 palmately veined or lobed leaves, no proper stipules; the flowers monoecious or dioe- 

 cious, with petals more commonly united into a cup or tube and also blended with 

 the calyx. Sterile flowers with 2 J- stamens, that is, two complete, with 2-celled 

 anthers, and one with a 1-celled anther; the cells usually long and contorted. Fer- 

 tile flowers with calyx-tube adnate to a 1-celled or 2 - 3-celled ovary ; the placentas 

 either parietal, or confluent in or projecting from the axis. Seeds anatropous, with- 

 out albumen. 



A peculiar but familiar family, of great diversity as to the fruit, &c, yet easy to recognize, 

 widely distributed over the world, but mainly indigenous to warm regions. Chiefly important 

 for the esculent fruits it produces (Melon, Watermelon, Cucumber, Pumpkin, Squash, &c), and 



