7. Solidago occidentalis (Nutt.) T. & G. Fig. 748. 



Rhizomatous perennial; stems simple, erect, 10-20 dm. tall, paniculately 

 branched in inflorescence; herbage glabrous; leaves numerous, linear, entire, 

 sessile, dark-punctate, 2-5 cm. long; inflorescence leafy-bracteate; heads small, 

 numerous, corymbosely disposed throughout inflorescence; involucre about 4 mm. 

 high, light-green or yellow; phyllaries linear-lanceolate, chartaceous; ray flowers 

 15 to 30, 1.5-2.5 mm. long, the disk flowers fewer; achenes turbinate. 



Very common in marshes and along irrigation ditches in N. M. (Dona Ana 

 Co.) and Ariz. (Navajo, Coconino and Cochise cos.), July-Sept.; Alta. to B.C., 

 s. to N.M., Ariz, and Calif. 



8. Solidago spathulata DC. var. nana (Gray) Cronq. 



Perennial from a caudex or short rhizome, 5-20 cm. tall, glabrous to scabro- 

 hirtellous in the inflorescence, usually more or less glutinous (at least the pedun- 

 cles and involucre); basal leaves spatulate or obovate, toothed or subentire, 

 blunt or rounded, to 15 cm. long (including the rather well-marked petiole) and 

 3 cm. wide, mostly persistent, the cauline ones progressively reduced and generally 

 few; inflorescence mostly short and compact, not secund, the heads often long- 

 pedunculate; involucre 4-6 mm. high; phyllaries evidently imbricate, commonly 

 blunt; rays 5 to 10, mostly 8; disk flowers about 13. 5. decumbens Green. 



In a variety of habitats but in the mountains often found along streams or on 

 seepage slopes or in wet meadows, in N. M. (Taos, Rio Arriba, San Miguel, 

 Santa Fe and Sandoval cos.) and Ariz. (Greenlee and Coconino cos.), June- 

 Sept.; the species from Yuk. to Que., s. to Calif., Ariz., N.M. and Va. 



11. Aster L. Aster 



Annual or usually perennial herbs, when perennial often with caudexes or 

 horizontal rhizomes; leaves when present alternate, not dissected, usually sessile; 

 perennial species usually with basal leaves dissimilar to cauline leaves and the 

 latter usually passing into the much-reduced leaves of the head-bearing branchlets 

 which are usually leafy to the summit; disk flowers present and perfect, their 

 corollas yellowish or less commonly tinged with blue, rose or violet; ray flowers 

 present, fertile, their corollas white or bluish-white or violet or even rosy at least 

 on the underside but never yellow; heads usually numerous and borne at the ends 

 of the usually leafy branches; head-bearing branchlets usually aggregated into 

 paniclelike inflorescences; receptacle of head flat or slightly convex; disk corolla 

 consisting of a basal cylindrical tube plus an expanded usually funnelform limb, 

 the limb consists of a throat plus 5 lobes; phyllaries in several series, imbricate, 

 the outer ones usually green at least near the tip and often on part of the midrib; 

 pappus of numerous capillary bristles in essentially a single series, similar in 

 disk and ray; achenes more or less flattened, with one or more ribs on the faces; 

 style branches usually subulate. 



Aster has several hundred species, mostly in temperate regions. It is one of our 

 more difficult genera, both as to its over-all circumscription and the limitation of 

 the species contained. Only complete specimens, with rhizomes and mature flowers 

 (with anthers exserted), can be determined with any degree of confidence. 



1. Distribution in New Mexico and Arizona, primarily montane (2) 



1. Distribution in Oklahoma and Texas (13) 



2(1). Upper leaves tiny, scalelike, entire; stems suflfrutescent; plants tall, essen- 

 tially glabrous (3) 



2. Upper leaves not tiny and scalelike; stems strictly herbaceous (4) 



3(2). Heads discoid; stems intricately branched; achenes silky 4. A. intricatus. 



3. Heads radiate; stems often spiny; achenes glabrous 1. A. spinosus. 



. 1615 



