of some Phanerogamic Parasites. 325 
EXPLANATION OF FIGURES IN PLATES 
XIIL XIV, AND XV. 
Illustrating Mr. Peirce’s paper on the Haustoria of Phanerogamic Parasites. 
PLATE XIIL 
Cuscuta americana , L. 
Fig. 1. Parasite twining about twig of Mimosa , a; b, Mimosa-twig showing 
perforations by haustoria ; c, parasite nat. size, and d } enlarged, showing haus- 
torial discs. 
Fig. 2. Cross-section of young Cuscuta- stem 2-3 cm. above youngest haustorium. 
x 20. 
Fig. 2'. Cross-section through abortive haustorium. x 20. 
Fig. 3. Radial section through vascular bundle of Cuscuta- stem. E, toward 
epidermis ; p, parenchyma ; a , air-cavity ; d, pitted ducts ; c, cambium ; cc, com- 
panion-cell of sieve-tube s. x 125. 
Fig. 4. Radial section of Cuscuta- stem showing young haustorium imbedded in 
cortex and overlaid by ‘ cushion ’ ; haustorium-cells only in outline, x 75. 
Fig. 4'. Development of ‘cushion-cells’ from epidermal. Nuclei large and 
near tips of cells, x 220. 
Fig. 5. Cross-section of stem, showing young haustorium. e, epidermis; 
g, growing-point, x 1 25. 
Fig. 6. Cross section of parasite (red) and host (brown) ; bifurcation of haustorial 
xylem at b. Mimosa. x 20. 
Fig. 7. Cross-section of host (longitudinal of haustorium) ; host brown, parasite 
red shading, red lines are callus-plates ; s, sieve-tubes ; t, tracheids ; union of 
t with xylem x of host ; c, cambium, x 75. 
Fig. 8. Cross-section of parasite (red) and host (brown) ; bifurcation of 
haustorium at f ; b } fibro-vascular bundles of host ; c, cortex ; p, pith. Apocynum 
sp ? x 20. 
Fig. 9. Cross-section of parasite (red) and host (brown) ; P, Cuscuta ; cork of 
host ; c, cortex ; H, haustorium ; S, sclerenchyma ; sb, soft bast ; w, wood ; /, pith. 
Fig. 10. Cross-section of haustorium in mother-plant : e, epidermis ; c, cortical 
parenchyma ; d } cortex of haustorium ; g, central cylinder with young bundles a, b. 
x 20. 
Fig. 11. Cross-section of haustorium, bundles a and b of Fig. 10; p, phloem ; 
c, cambium ; t, tracheids. x 220. 
Fig. 12. Longitudinal section through haustorium to show union of its xylem 
and phloems with two bundles of mother-plant ; t, young tracheids ; s, s, young 
sieve-tubes ; H, basal region of haustorium ; C, interfascicular parenchyma ; 
E, direction of epidermis and tip of haustorium ; /, latex-tubes, x 2 20. 
Z 2 
