574 ON SEEDLINGS 



(Enothera bistorta, Nutt. (figs. 367, 368). 

 Seeds 1-1*25 mm. long, '33-'5 mm. wide. 



DEVELOPMENT OF COTYLEDONS. 



Immediately after germination the cotyledons are oblong, obtuse, 

 entire, sessile with a few long, scattered, glandular hairs, especially 

 at the base. Hypocotyl with a few glandular hairs at its apex. 

 Cotyledons often unequal, owing to their greater or less development 

 in the seed, and one folding over the other. 



Six days after germination the base has become elongated, 

 petiole-like, and glandular-pubescent, suddenly narrowed to a short 

 petiole or subsessile ; the upper half remains rotund and glabrous 

 except at the base and possibly a few short hairs underneath. 



Eight days after germination (fig. 

 367) they have elongated considerably, 

 the upper true cotyledonary part en- 

 larging, but otherwise remaining un- 

 altered, while the foliar basal and 

 narrow part has become linear, entire 

 or sometimes with a minute tooth on 

 either side, glandular-pubescent, sud- 

 denly narrowed at the very base. 



The lower portion elongates greatly, 

 FIG. 367. -(Enothera bistorta. and ^ ^timate stage of the cotyledons 

 (fig. 368) is linear, tapering at the base 



into a petiole ; upper part or true cotyledon rotund or oval, en- 

 tire, glabrous, very short, without an evident midrib ; lower part 

 linear, terminating abruptly in the upper part, tapering gradually 

 to the base, with one or two minute and distant teeth on each 

 side, thinly hairy, greyish-green with an evident midrib sunk on 

 the upper surface, and prominent beneath ; petiole semiterete, flat- 

 tened above, very thinly hairy, or at length nearly glabrous. 



First eight leaves radical, alternate, linear, obtuse, tapering at 

 the base into the petiole, thinly silky with adpressed pubescence, 

 minutely and distantly toothed at the margin, greyish-green, more 

 or less distinctly marked near the margin with black dots, with a 

 very distinct, colourless midrib, flattened above and prominent 

 beneath ; petioles semiterete, flattened above, thinly hairy at the 

 margins, colourless. (Thirty-four days after germination.) 



(Enothera macrantha, A. Gray (fig. 369). 



Primary root tapering downwards and furnished with lateral 

 fibres, annual. 



