2g0 BOTANICAL GAZETTE [OCTOBER 
ied Dolophragina Fenzl, Dufourea Gren., Eremogone Fenzl, Euthalia Rupr., 
obill. & Cast., Leptophyllum Ehrh., Lepyrodiclis Fenzl, Odontos- 
to show the widely divergent views which have been held as to the generic 
limitations of the group. 
Mr. Williams recognizes seven subgenera of which the salient characters 
may be summarized thus: 
Euarenaria. Glands of disk obsolete; capsule-teeth 6. 
Eremogoneastrum. Glands prominent; capsule dehiscent to below the 
middle by six valves; mostly cespitose perennials. 
Pentadenaria. Glands 5; capsule 6-toothed; perennials, often suffruti- 
se. 
Dicranilla. Glands present; capsule dehiscent beyond the middle by six 
valves ; flowers solitary, terminal, minute; S. American tufted alpine species. 
Arenariastrum. Capsule dehiscent by 4 teeth ; glands inconspicuous. 
Odontostemma. Capsule dehiscent by 4 valves; filaments bidentate near 
the base. 
Macrogyne. Capsule dehiscent by 4 valves; styles much exserted. 
All but the last subgenus are again divided into two to five tolerably well 
marked sections. Our interest naturally centers upon the treatment of the 
North American species. Of these Mr. Williams recognizes fourteen, which 
he arranges thus: 
Subg. EUARENARIA, 
Euthaliana (with seeds granulate-tuberculate). 
A. Benthamii. 
A. serpyllifolia, 
§ Leiosperma ene smooth globose, reniform, or lenticular seeds). 
A. an Sat osa 
. Saxosa. 
ya eee (with smooth, compressed, pyriform or oblong seeds). 
- congesta. 
A. Franklinii. 
Subg. PENTADENARIA. 
A. ursina. 
A. capillaris. 
A. macradenia. 
A. Fendleri. 
A. ciliata 
This subdivision is certainly natural and theoretically clear. It is to be 
feared, however, that the gland distinction between Pentadenaria and Euare- 
a 
; 
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ee 
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4 
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