376 T. Holm—Triadeniim Yirginicum {L.) Rafin. 



make a comparison between the two. Bat whatever the result 

 may be, Linneeas's Hypericum Yirginicum can no longer be 

 considered as a species of this genus, and even if Rafinesque 

 did not give but a mere hint as to its probable validity as a 

 genus, Triademim^ nevertheless, appears tenable and indeed 

 quite distinct from Hypericum and the other " generic syno- 

 nyms." 



Brookland, D. C. 



Bibliography. 

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 Coulter, John M. : Hypericaceoe in Synopt. Flora of N. Am,, i, 



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 Solereder, Hans : Systematische Anatomie der Dicotyledonen, 



p. 134, Stuttgart, 1899. 

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1836). 

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I'Hypericum calycinum (Journ. de Bot. 17 : 56. Paris, 1903 



(not seen). 



EXPLANATION OF FIGUEES, p. 371 

 Triadenum Virginicum (L.) Raf. 



Figure 1. — Rhizome of a specimen, collected in October ; natural size. 

 S = base of fruitbearing stem ; T = two tuberous stolons, devel- 

 oped from the axils of the cotyledons ; R = the primary root. 



Figure 2. — Rhizome of another specimen, collected at the same time ; nat- 

 ural size. St. — a slender stolon, developed from the axil of 

 one of the lower stem-leaves ; the other letters as above. 



Figure 3. — Rhizome of a specimen, collected in June ; natural size. This 

 rhizome represents a tuberous stolon, of which the terminal 

 bud has developed into an above-ground stem. B = an axillary 

 bud, "still dormant ; St. = the beginning development of an 

 axillary stolon. r= secondary roots, developed above the axil- 

 lary buds. 



Figure 4. — Transverse section of a leaf. Ep = epidermis of the lower face ; 

 D = a duct. X 320. 



Figure 5. — Transverse section of a leaf ; the duct (D) is here located in the 

 leptome ; V = vessels. x 320. 



Figure 6.— Transverse section of stem. Ep. = epidermis. D = a duct, 

 located in the cortex. x 320. 



Figure 7. — Transverse section of stem. End = endodermis. D = a duct ; 

 L = leptome ; V = vessels. x 320. 



Figure 8. — Transversa section of a tuber. C - cortical parenchyma ; D = 

 duct, of which four are visible in this section. x 75. 



