1^8 



EXPLANATION OF PLATE XXXVIIL 



I. The Buck-thorn Tribe. — I. A twig of Christ's- thorn (Pa- 

 liurus australis). — 2. A flower magnified ; a a petals, b h lobes of the 

 calyx. — 3. A petal separate. — 4. A stamen. — 5. A section of the ovary 

 and disk ; a the disk, b the part where the ovary grows to the side of 

 the calyx. — 6. A ripe fruit, natural size. — 7. A seed. — 8. A section of 

 the same, exhibiting the flat embryo. 



IL The Spurge Tribe. — 1. The upper part of the stem of Dwarf 

 Spurge (Euphorbia Peplus), with the common leaves at the bottom, 

 and the floral leaves occupying the remainder of the specimen ; a a 

 flower-heads. — 2. A flower-head, magnified; a a glandular divisions of 

 the involucre ; b the pistil-bearing floret in the centre. — 3. A section 

 of the involucre ; a a the glandular lobes ; b b the inflected lobes ; c the 

 stalk of the pistil-bearing central floret, surrounded by the naked stamen- 

 bearing florets. — 4. A stamen-bearing floret ; a the joint between b the 

 pedicel, and c the filament. — 5. A section across a nearly ripe fruit, 

 shewing the short wings at the angles, and the seeds with the embryo 

 lying in the centre of the albumen of each. — 6. The same ovary, 

 uncut. — 7. A seed ; a its caruncula. — 8. A longitudinal section of the 

 same, with the embryo surrounded by albumen. 



