42 



Wood head : Notes on the Bluebell. 



In collecting' material for study during- May and June, 

 numerous tiny bulbs and seedling plants in various stages of 

 development were found growing amongst the old plants. At 

 that time of the year seedlings may be found varying in age 

 from a few months, to plants one, two, or more years old. Two 

 of these young plants are shown in Fig. i, d and e. The first 

 of these (d) represents a seedling in the first year of its gTOwth. 

 Emerging- from the black shining- seed is the cotyledon, a tubular 

 structure surrounding the base of the plant, and spring-ing from 

 within this tube is a single narrow leaf. To study the early 

 stages of development of such a plant, material must be col- 

 lected in November. If at that time we search amongst the 

 dead and decaying- leaves of oak and sycamore, and in the 

 vicinity of fallen withered fruit stalks of the bluebell, we shall 

 find numerous seeds in various stages of germination, two of 

 these are shown in Fig. i, a and b ( x 2). 



The seed is globular, with a hard, black, shining coat; on 

 one side is a tiny projection indicating the positions of hilum 

 and micropyle. A section of such a seed shows an outer coat 

 of thick-walled, black-brown cells, and within this, two layers of 

 thinner-walled cells ; these represent the primine and secundine 

 of the ovule. Next to this coat is a massive tissue, the endo- 

 sperm, the cells of which have thick, curiously pitted walls of 

 cellulose, and cavities crowded with starch grains (Plate III., 

 I and 2). In the centre of this tissue is the embryo, a 

 diagram of which is seen in Fig. i, h. The single seed-leaf is 

 large, with a solid tip, below it is curved in such a way as to 

 enclose the plumule in a cavity, leaving only a narrow, elongated 

 slit on one side (Fig. i, h). When germination begins this 

 leaf elongates and bei:omes a long, hollow tube with the plumule 

 at the base. Sections through this region show this stem bud 

 surrounded by the thickened base of the cotyledonary tube. 

 Plate III. : 3 is from a microtome section ; and 4 is from the 

 same series at a lower level just before it joins on to the root 

 stele. The first foliage leaf grows up within the tube, keeping 

 pace with it, the lateral slit, already noticed in the embryo, 

 being a little above the leaf tip (Fig. i, s). Among a number 

 of seedlings collected was found a curious instance of apparent 

 fusion of two seedlings (Fig. i, c), but careful examination 

 showed that the tiny root-tip of one seedling had pushed its 

 way into the slit and grown down the tube of another. The 

 radicle elongates, and for a time functions as the sole root of 

 the young plant, being richly clothed above with root-hairs. 



Naturalist, 



