LFCOPODTNEAE. HOMOSPOROUS LYCOPODIACEAE. 



279 



Lycopodineae, and have a short broad stalk; the capsule is more or less reniform, 

 having the broader diameter in the direction transverse to the median plane of the leaf, 

 and opens by a slit which runs in this direction over the apex and divides them into 

 two valves which remain united at the base. The rather small spores are between 

 round and tetrahedral in form, very numerous, of uniform size and shape, and with a 

 variety of markings on the exosporium. The sporangia originate in a group of 

 superficial cells of the base of the leaf, and appear at first as flat prominences which 



v 



FIG. 227. A forked sporanglferous branch of Lycopodium Ckamaecyparissus in longitudinal section, slightly 

 magnified ; /"/"the axile vascular body, b b leaves, .r .r young sporangia. 



occupy the breadth of the leaf. An axile longitudinal section through a young 

 sporangium shows here also a hypodermal archesporium-ccll, but with so great a 

 breadth of the sporangial protuberance it may be questioned whether the archesporium 

 is not really a row of cells. The wall of the sporangium is at first composed of one 

 layer of cells, which however subsequently splits, and this process is repeated in the 

 inner of the two layers thus formed ; the innermost of the three resulting layers of 

 cells forms the layer of lapelal cells, which becomes separated from the adjacent cells 



