3 o8 



BOTANICAL GAZETTE 



[APRIL 



3. Sclerenchyma (scl). — Small, # thick- walled, pitted, irregular! 

 arranged cells make up this layer, which has no sharp line of demarka- 

 tion from the preceding layer. 



4. The parenchyma (p) consists of several layers of small thin- 

 walled cells. 



•p 



One layer of parenchyma cells makes up 



this indistinct inner tissue. 



The perisperm (fig. 4Q, N) of several cell layers, endosperm 

 (fig. 4Q, E) of one layer of thick-walled cells, and embryo (fig. 49* Q 

 are like those described in the introduction. 



Fig. 



thria 



50- 

 scabra 



Seed. Xi. 



Melo- 

 Cogn. 



Melothria scabra Cogn. 



(fig. 50) is 4-5 



mm 



long 



n' 



2 



m 



m broad, and o.75 mm thick, flattened, pointed, 



and smooth. 



{fii 



Con- 



sists of five layers, and has a 

 microscopic structure resembling 

 that of Cucumis sativus. 



Seed 



K9Ji. 



Fig. 51. — Melothria scabra Cogn. 

 in cross-section; 5, spermoderm 

 consisting of ep, epidermis, sub, subepi- 

 dermal layer, scl, sclerenchyma, p, paren- 

 chyma; N, perisperm ; £, endosperm; C, 

 cotyledon with ep, epidermis, and meso- 



Epidermis (ep).-A P ali " 

 ade layer, 270 /* in width, form 

 the outer layer, which, a> O 

 Cucumis, is frequently absent 

 on the dry seeds. The walls are 

 thin except for a single, straight 

 pointed rod on each radial wall. 

 2. Subepidermal layer (sub). 



This single layer is compos 1 <* 

 thick-walled cells having pit^na 



distinct laminations. Atthee g 

 of the seed the layer increa^ 

 from two to five cells in thick** 

 the outer ones being elong 



ted 



radially. 



3 



/) 



■Small 



itted cells longitudinally elong 



cotyledon with ep, epidermis, an,! meso- * , . ' fVl _ third W*' 



Phyllcontaininga/.aleuronegrains. X 160. ated, make up tne 



P 



