PLATANACEAE 369 



stipules. Flowers perfect and pistillate in axillary clusters, involucrate by 

 small leafy bracts. Staminate calyx 4-parted. Pistillate calyx tubular-ventri- 

 cose, 4-lobed. Achene ovoid, enclosed by the persistent calyx. All continents, 

 7 species. (The ancient Latin name of the Italian species because growing on 

 walls.) 



1. P. debilis Forst. Stems very slender, several from the base, diffuse, 4 to 

 10 inches long; herbage pilose or hispid; leaves ovate to ovate-lanceolate, 

 rounded at base or abruptly cuneate, often shortly attenuate to the obtuse 

 apex, 3 to 12 lines long, or the lowest very small, on petioles 1 to 3 lines long ; 

 clusters few-flowered. 



Moist shady places : Southern California and north to Inyo Co. North and 

 South America, Asia, Australia. 



Locs. San Diego; Witch Creek, Alderson; Palm Canon, Jepson 1365, Hall 1882; Menifee, 

 Alice King; San Bernardino, Parish; Arrowhead Sprs., Setchell; San Gabriel Mts., ace. 

 McClatchie; Eedondo, Braunton 345; Santa Cruz Island, Brandegee; Santa Barbara, ace. 

 fates. 



Kef. PARIETARIA DEBILIS Forst. Prodr. 73 (1786), type loc. New Zealand. 



PLATANACEAE. PLANE FAMILY. 



Large deciduous trees with alternate ample palmately lobed leaves and 

 sheathing stipules ; dilated base of petiole enclosing the bud of the next season ; 

 bark falling away in thin plates. Flowers monoecious, the staminate and the 

 pistillate on separate axes, closely packed in separate ball-like clusters dis- 

 tributed at intervals along a terminal very slender axis, the inflorescence thus 

 appearing moniliform. Receptacles very hairy and individual flowers difficult 

 to segregate. Calyx and corolla none. Stamens with long anthers and very 

 short filaments densely crowded on a globose fleshy receptacle. Pistils with 

 interspersed clavate truncate bracts, crowded on a similar receptacle; ovary 

 1-ovuled; style one, filiform, laterally stigmatic. Fruit a coriaceous nutlet 

 with tawny hairs about the base. 



Bibliog. Griggs, E. F., Characters and Eelationships of the Platanaeeae (Bull. Torr. Club, 

 36: 389-395, 1909). 



1. PLATANUS L. PLANE TREE. 



The only genus. Northern hemisphere, 5 species. (Greek platus, broad, 

 referring to the ample leaves.) 



1. P. racemosa Nutt. WESTERN SYCAMORE. (Fig. 66.) Tree 40 to 90 feet 

 high with a massive crown of wide-spreading limbs; leaves 3^ to 9 (or 13) 

 inches long, commonly broader than long, parted into 3 to 5 broad, spreading 

 fingers or lobes ; margin entire or with few small teeth ; stipules very conspicu- 

 ous when full grown, roundish or angular in outline and encircling or sheath- 

 ing the stem; ball-like flower clusters, 2 to 7 in number, distributed at inter- 

 vals along a pendulous and very slender axis borne at or near the end of a 

 branch; balls falling to pieces in the winter, releasing the seed-like nutlets. 



Common and sometimes abundant in river-bottoms. Sacramento Valley 

 southward through the Sierra Nevada foothills, the San Joaquin Valley and 

 South Coast Ranges to the coast region of Southern California. Lower Cali- 

 fornia. Individual trees frequently attain great size. The trunks are often 

 remarkable for their great divergence from the perpendicular, due to the 

 shifting character of the soil in stream beds. Not known in North Coast 

 Ranges. Northernmost station at Anderson, Tehama Co. 



Kefs PLATANUS RACEMOSA Nutt. Sylva, 1: 47, t. 15 (1842); Jepson, Fl. W. Mid. Gal. 275 

 (1901), Silva Gal. 247 (1910). 



