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MORPHOLOGY; DIAGNOSIS. 



the testa is very lax. In colour the testa varies from black (P. furfuracea), slate grey 

 (P. gibbera), dark brown (P. rhinanthoides), or rusty brown (P. siphonantha), to pale tawny 

 (P. megalantha), or pale straw colour (P. Oederi). But colour is not, and will probably 

 never become, a character of great practical value in distinguishing the seeds of different 

 species of Pedicularis, because the differences are so often mere variations of shade not 

 equally appreciated by all observers; because these shades appear to become lighter as 

 the seeds ripen; and finally, because there is no guarantee that the seeds are not, 

 sometimes at least, altered in colour while the specimens are being dried. The most 

 useful characters afforded by the seeds are those derived from the nature and the 

 markings of the testa. Sometimes this is thin and closely adpressed to the albumen 



(P. lonqiflora), and then the surface is only marked by slight longitudinal striae; at other 

 times it is much more extensive, the albumen not nearly filling it, and is then lax 

 and deeply pitted. All possible intermediate conditions occur, and these are best 

 expressed in terms of the pitting which results, and which is the most prominent 

 feature of the seed. 1 There is in most cases a distinct appearance of longitudinal 

 ridging that runs meridionally from apex to base. The ridges are only an accentuation 

 of the condition producing the striation that exists when the testa is closely adpressed 

 to the albumen, but in addition to this the furrows between are crossed by transverse 



lets that complete the periphery of the characteristic pits. Where these transverse 

 d'dets are narrower and less in relief than the meridional ridges — and this is the 



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usual condition— a pitted and furrowed appearance go together. But where the trans- 

 verse ridges equal the meridional ones in width and height, a net-like appearance is 

 imparted to the testa, and this becomes more and more apparent when the testa is 

 obviously more extensive in relation to the albumen (P. brevifolia, denudata), while not 

 infrequently where the testa is very extensive indeed (P. trichoglossa, Clarkei), the peri- 

 phery of the pits becomes irregularly hexagonal and the surface assumes a honeycombed 

 appearance. As a rule, the markings are uniform throughout the testa, but sometimes 

 (P. pectinata, comp tonice folia , dolichorrhisa) the funicular aspect of the seed is thus 

 irregularly (and generally very irregularly) honeycombed, while the remainder of the 

 surface is ridged and pitted in a regular manner. And sometimes where the testa is 

 very loose, the ridged arrangement still persists (P. alaschaniia) and produces a gilled 

 appearance ; the meridional gill-like ridges have transverse pit-forming ridglets on both sides. 



The albumen is firm, and the embryo, which is straight, occupies a mesial cavity in 

 the upper portion of its mass. Usually the embryo is from one-fourth to one-third the 

 length of the albumen, rarely (P. pycnantha) exceeding one-half. The radicle points 

 upwards; the semi-cylindric cotyledons in the opposite direction. 





CHAPTER III.— DIAGNOSIS AND CLASSIFICATION OF SPECIES. 





In diagnosing the species of Pedicularis, characters afforded by habit are of compara- 

 tively small value. This is partly because habit varies greatly within the limits of 

 individual species, partly because quite distinct species very frequently display remark- 

 able identity of habit. This identity is not, however, necessarily confined to vegetative 

 organs alone, as is the case with P. lachnoglossa and P. Parri/i ; P. Roylei and P. verti- 

 cillata; P. megalmtha and P. chincmis, but may extend to floral characters, and this to 



1 Cf, plate 36 and plate 37 for examples of the conditions detailed in the text. 



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