106 Morris : Revision of Species of Plantago 



M 



of Sciences, 



and Dr. E. L. Greene, in allowing the use of their specimens and 

 libraries. 



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In the key which follows, the synopsis of the genus is adapted . 

 from Gray's Synoptical Flora, except the group indicated by two 

 asterisks (**) which is prepared for the identification of the species 

 treated in this paper. 



The species treated are from North America exclusive of 

 Mexico and Central America. • 



PLANTAGO 



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§ I. Flowers all perfect ; lobes of the corolla not closed over the pyxis ; stamens 

 four. 



* Root perennial, biennial, or annual in P. decipiens ; flowers dichogamous, pro- 

 terogynous ; the style projecting from the apex of the unopened corolla ; the anthers 

 long-exserted on capillary filaments after the corolla has expanded ; seeds two or more, 

 not hollowed on the face except in P. lanceolate. 



** Root annual ; the petioles dilated at their bases ; flowers heterogonous, in the 

 majority of individuals cleistogamous ; the lobes of the open corolla wide-spread, nearly 

 equalling the tube ; seeds solitary in the two cells, deeply hollowed on the face. 

 Bracts linear to lanceolate. 



Bracts aristate, two or more times as long as the flowers. 

 Spikes more or less compact ; plant dark green. 



Spikes large, 20-many flowered. I. P m aristata. 



Spike small, 2-20-flowered. 2. P. aristata Nuttallii. 



Spikes more or less interrupted ; plant light green. 3. P. spinulosa. 

 Bracts not aristate, not over two times as long as the flowers. 



Bracts linear-subulate to narrowly lanceolate, narrow at the ba=e. 



Spikes narrow-cylindrical ; whole plant white-woolly, light green. 



4. P. Purshii. 

 Spikes narrow-cylindrical, at length interrupted ; whole plant silvery- 

 g . silky, dark green. 5. p. argyrea. 



Spikes thick, conspicuous on account of the large corollas ; plant villous, 

 dark green. 6. P. Helleri. 



Bracts lanceolate or triangular, wide at the base. 



* 



Plant erect ; spikes coarse. 



Plant glabrous or nearly so, dark green. 7. P. Wrightiana. 

 Plant villous, bright green. 



Bracts more than 3 mm. long ; sepals scarious, with brown 



midribs. 8. P. dura. 



Bracts not more than 3 mm. long ; sepals herbaceous, green. 



9. P. inflexa. 

 Plant spreading ; spikes delicate. IO. P. lanatifolia. 



Bracts oblong to ovate or orbicular. 



Plant villous ; bracts as long as the sepals or [in situ) equalling the calyx. 



