Exeerj)ta Botanica. 349 



The stipules are very variable in form and size^ in all the 

 species and on each individual, according as they "pertain to 

 the leaves of the flowering branches or to the leaves of the lux- 

 uriant shoots {jmusses gournumdes) [barren shoot sl;~\. Those 

 of the floral branches are very fugacious, membranous, sub- 

 scariose, chiefly liguliform ; those of the luxuriant shoots 

 {pousses gourmandes) being on the contrary less caducous, 

 subherbaceous, oval, ovali-oblong, ovali-lanceolate, oblongo- 

 lanceolate, oblong or sublinear, obtuse or pointed, or acumi- 

 nate. 



Certain modifications of the fructiferous involucres of C Co- 

 luma, having been found to be very constant, appear sufficiently 

 remarkable to establish the following varieties, though it is not 

 pretended that intermediate varieties may not exist as well as 

 other varieties equally distinct. Those here noted, with the 

 exception of one form referred to, that figured by Watson, 

 were observed on six trees in the Jardin du Roi. 



a. brachycarpa, Spach. — Coryhis Colurna, Wats,, Dendr. Brit., tab. 

 99. Involucre (1^ — 2 inches long) three times longer than nut, 

 pubescent (not setiferous) ; segments divided beyond the middle 

 into linear-lanceolate or demi-lanceolate straps (lanieres), very 

 acuminate, generally very entire. 



ft. trichochlamys, Spach. Involucre (15 — 18 lines long) one- 

 half longer to twice as long as nut, hispid, glandular ; segments 

 divided beyond the middle into linear-lanceolate or subfalciform 

 straps, rather broad, acuminate, some bi- or tri-furcate at the 

 summit, others very entire or dentate. 



y. macrochlamys, Spach. Involucre (2 inches long) 2 — 3 times 

 longer than nut, downy, not setiferous ; segments divided for 

 ^rd into linear-lanceolate or falciform straps, acute, unequal, 

 slightly jagged. 



2. leptochlumys, Spach. Involucre (about 1 inch long) A — i longer 

 than nut, not hispid, cottony ; segments divided nearly to their 

 base into denticulate or dentate or very entire or 3 -furcate 

 straps, acute, generally linear and narrow. 



€. avellanoides, Spach. Involucre (about 15 lines long) ird longer 

 than nut, downy, glandular, not hispid ; segments divided for 

 3^rd into mostly broad, oblongo-lanceolate, acute, inciso-dentate 

 lobes. 



2. CORYLUS AVELLANA, Linn. — Corylus americana, Mich.! Flor. 

 Bor. Amer. (et auct. Americ. plurimis*). — Corylus Avellana et 



* This pretended species is absolutely identical with C.ylvellann of Europe. 

 Michaux distinguished it by its amplified (i. e. much longer than the nut) 

 involucre, unequally multiiid, bristled with glandular hairs ; but this struc- 

 ture of the involucre is equally very frequent with the European C, Jvvl- 

 lana ; and moreover we have seen specimens of this same species gathered in 

 the United States, in wliich the involucre was perfectly similar to that of 



