

 Parietaria. PLATANACE.E. 65 



* * Annuals : inflorescence of mingled male and female fl,owers, iisually shorter 

 than the petioles : stipules very small. 



4. TJ. urens, Linn. Slender, erect or ascending, a foot or two high, with short 

 lateral branchlets, leafy throughout, with scattered hairs or nearly glabrous : leaves 

 thin, ovate or ovate-oblong, an inch or two long, coarsely and iucisely toothed ; 

 stipules small, free : flower-clusters mainly pistillate, rather close and nearly sessile 

 or more loosely panicled : fruiting sepals ovate, hispid on the margin, usually with 

 a single lateral bristle : akene a line long. 



An introduced weed from Europe. 



2. HESPEROCNIDE, Torrey. 



Distinguished from the last group under Urtica only by the pistillate perianth, 

 which is a membranous compressed oblong-ovate sac, with a minutely 2 - 4-toothed 

 oritice. Annual herbs ; only two species, the second belonging to the Sandwich 

 Islands. 



1. H. tenella, Torrey. Slender and weak, often a foot or two high, simple or 

 branched, somewhat hispid with branching hairs and bristly : leaves thin, ovate, 

 to 1| inches long, on short slender petioles, obtusely serrate : flower-clusters loose, 

 shorter than the petioles : perianth thin, hispid with hooked hairs, | to f line long 

 in fruit : akene membranous, striately tuberculate with minute rough points. 

 Pacif. R. Kep. iv. 139 ; Weddell, DC. Prodr. xvi 1 . 68. 



In the shade of rocks, Napa County and southward; Guadalupe Island, Palmer. 



3. PARIETARIA, Tourn. PELLITORY. 



Flowers perfect and pistillate, in axillary cymose clusters, involucrate-bracted : 

 perianth in the perfect flowers 4-parted, in the pistillate tubular- ventricose and 

 4-cleft with connivent lobes : style slender or none : stigma spatulate, recurved, 

 densely tufted : akene ovoid, shining, enclosed in the dry brownish nerved calyx : 

 albumen scanty. Low annuals (our species), unarmed ; leaves alternate, entire, 

 3-nerved, without stipules. 



A widely distributed genus of 8 or 10 species, two of them American. 



1. P. debilis, Forster. Very slender, 3 to 12 inches high, usually diffusely 

 branching from the base, somewhat hispid : leaves small, broadly ovate, obtuse, 

 rounded at base or abruptly cuneate, 2 to 6 lines long or more, about equalling the 

 slender petioles : clusters few-flowered ; bracts linear or narrowly oblong, short (| 

 to 1 line long), about equalling the flowers : akene | line long. Weddell, DC. 

 Prodr. xvi 1 . 235 45 . 



Southern California, from Santa Barbara to San Diego, and eastward in various forms across 

 the continent, southward to Chili, and nearly everywhere within a like broad zone around the 

 globe. 



P. PENNSYLVANIA, Muhl., is a more northern species, common in the Atlantic States and col- 

 lected as far west as the mountains of N. E. Nevada. The leaves are lanceolate, more attenuate 

 at base, and often 2 inches long or more ; bracts longer and exceeding the flowers ; akene some- 

 what larger. 



ORDER LXXXV. PLATANACE.2E. 



Monoecious trees, with flaky bark, alternate palmately nerved and lobed leaves, 

 with sheathing deciduous stipules, and the hollowed petiole covering the bud ; 



