418 MINNESOTA BOTANICAL STUDIES. 



tened in the dry, ripe seed but swell out in seeds which have 

 been soaked in water. The tegmen consists of a single layer of 

 small rectangular cells with thick periclinal and thin anticlinal 

 walls. The cell walls are of a dull brownish color and the cav- 

 ities are without contents. 



Germination takes place in from four to six weeks when 

 seeds are placed under favorable conditions. The cotyledons 

 generally escape from the seed-coat before appearing above 

 ground. This is easily done because by this time the endo- 

 sperm has been completely used and the seed-coat is likely to 

 be somewhat rotted during the long period of germination. 



Morphology of the Seedling. In the young seedling the cot- 

 yledons are small, the blades being generally about 4 mm. in 

 length when they first emerge above the surface of the soil. 

 They increase considerably in size, becoming 8 mm. long and 

 6 mm. wide. They are ovate, bluntly pointed, with three prin- 

 cipal veins from which spring conspicuous secondary veins. 

 The petioles are connate from their bases to a point only a few 

 millimeters from the blades. The structure formed of the united 

 petioles emerges above the surface of the soil in the form of an 

 arch, thus simulating a hypocotyl. (See Fig. i.) The connate 

 bases of the cotyledons form a dome-shaped structure covering 

 the growing point of the shoot. This structure may be termed 

 the cotyledonary sheath. The development of the foliage leaves 

 causes a rupture of the cotyledonary sheath. Through the 

 opening formed the first and succeeding leaves emerge. (See 

 Figs. 2 and 3.) The cotyledons wither and finally disappear 

 about the sixth week after germination. The first internodes of 

 the stem do not elongate and the sub-aerial portion of the plant 

 consists only of a rosette of long-petioled leaves, until the some- 

 what scape-like flowering stem is produced. The early foliage 

 leaves show considerable variation in the blade. The first is 

 palmately tri-lobed with narrow sinuses. In some specimens 

 the lobes are pointed, in others rounded. The separate lobes 

 are sometimes rather deeply one- to two-toothed. Later leaves 

 may be similar or may be five-lobed, the lobes generally mucro- 

 nate, or acute, not rounded. The young seedling of the plant 

 studied resembles that of Delphinium nudicaule, first observed 

 by Asa Gray,* and accurately described by Darwin. f Lub- 



*Graj. Botanical Text Book, Ed. VI, i : 22. 1879. 



t Darwin. The Power of MovementMn Plants, "p. 80 (American Edition). 



