PEA FAMILY 563 



celled or becoming 2-celled by intrusion of one or both sutures. Seeds few to many, small, 

 on slender funiculi. [Ancient Greek name of some leguminous plant.] 



About 1,500 species, of wide geographical distribution, abundant in northern Asia and western North 

 America. Type species, Astragalus Christanus L. 



Fruit wholly 1-celled, the lower suture rarely sulcate but if so not forming a partition. 



Pod 1 more or less compressed laterally, both sutures prominent. 



Leaflets spine-tipped; pods 1-4-seeded. I. Kentrophyta. 



Leaflets not spine-tipped; pods with several to many seeds. II. Homalobus. 



Pod not laterally compressed, or only slightly so, the lower suture not prominent; leaflets not spine-tipped. 



Pod usually coriaceous or woody in texture. 



Valves of the pod not winged. 



Calyx campanulate; pods erect. III. Cnemidophacos. 



Calyx cylindric; pods horizontal. IV. Xylophacos. 



Valves of the pod winged. V. Pterophacos. 



Pod membranous or papery, rarely rather firm. VI. Phaca. 



Fruit perfectly or imperfectly 2-celled, the lower suture inflexed, forming a false, complete or partial partition 

 (septum). 



Pod imperfectly 2-celled, the septum not meeting the upper suture. 



Pod membranous or papery, more or less inflated. 



Body of the pod oval or oblong in outline, the sutures equally curved or the upper more than the 

 lower, the cross-section elliptic to orbicular. VII. Atelophragma. 



Body of the pod lunate, the lower suture more strongly curved than the upper, the cross-section 

 deltoid-ovate. VIII. Phacomene. 



Pod coriaceous or woody. 



Pods linear or linear-lanceolate in outline, the lower suture often sulcate, and the cross-section 

 usually cordate, rarely suborbicular. IX. Tium. 



Pods oval to elliptic in outline, suborbicular in cross-section, the sides usually a little compressed. 



X. Brachyphragma. 

 Pod completely 2-celled, the septum meeting the upper suture. 



Pods membranous or papery, inflated. XI. Cystium. 



Pods coriaceous, not strongly inflated. 



Body of the pod elongated, linear or rarely oblong in outline. 



Pods sessile. XII. Hamosa. 



Pods stipitate. X. Brachyphragma. 



Body of the pod short, ovoid or broadly oblong in section. 



Pods distinctly stipitate. XIII. Hesperonix. 



Pods sessile or subsessile. 



Pods erect or ascending, neither didymous nor cross-wrinkled. 



XIV. Euastragalus. 

 Pods reflexed, more or less, didymous and cross-wrinkled. XV. Hesperastragalus. 



I. Kentrophyta. 



Perennial, diffusely branched; leaflets 3-9, subulate to linear-lanceolate, rigid, spinulose-tipped; flowers in 

 small axillary clusters; pods ovoid, flat, 1-celled, with both sutures prominent, 1-2-seeded. 



Stipules united only at base, more or less herbaceous; stems 3—4 dm. high, mostly erect; corolla ochroleucous. 



1. A. impensus. 

 Stipules united to the middle, scarious; stems scarcely 1 dm. long, spreading or decumbent; corolla purple. 



2. A. tegetarius. 



II. Homalobus. 



Perennial herbs, with rootstocks or woody caudex; flowers racemose; calyx campanulate; keel obtuse or 

 narrowed to a slender acute tip; pod usually more or less compressed, membranaceous or chartaceous, 1-celled 

 with no trace of a partition, both sutures prominent; seeds several to many. 



Pods sessile or subsessile. 



Pod broadly elliptic in outline, 4-5 mm. long. 3. A. tegetarioides. 



Pod linear in outline, 15-20 mm. long. 



Leaflets strigose and canescent on both surfaces; pods strigose. 4. A. strigosus. 



Leaflets glabrous above and green. 5. A. serotinus. 



Pods distinctly stipitate. 



Calyx not gibbous at base, less than half as long as the corolla; pod usually membranous. 

 Leaflets narrowly linear; pods dehiscent first at the base, splitting through the stipe. 

 Pods glabrous. 



Leaflets slightly strigose beneath or glabrous throughout. 6. A. stenophyllus. 



Leaflets strigose-cinereous on both sides. 7. A. MacGregorii. 



Pods strigose. 



Pods abruptly acutish at apex. 8. A. filipes. 



Pods acuminate at apex. 9. A. inversus. 



Leaflets linear to linear-oblong or oval; pods dehiscent first at apex. 



Pods glabrous. 10. A. Antisellii. 



Pods strigose. 11. A. gaviotus. 



Calyx strongly gibbous at the base, more than half as long as the corolla; pod rather coriaceous. 

 Sutures of pods not prominently thickened and coriaceous. 

 Pods straight or nearly so. 



Pods pendulous or divaricately spreading. 



Pods short-villous, not mottled, 20-25 mm. long. 12. A. collinus. 



1 In giving the measurements of the pod, "wide" or "broad" is used to denote the distance from suture to 

 suture, and "thick" the distance across the pod from valve to valve. 



