Thiselt on- Dyer. — Morphological Notes. 757 
causes may lead to the formation of adventitious roots in the 
Cactaceae, and states that adventitious roots are often seen 
starting from a point of the stem which has been the seat of 
a contusion. A haustorium forcing its way into the neigh- 
bourhood of the pericycle or cambium might have caused 
root formation. 
It is evident from the facts contained in these notes that 
there is still a good deal to be cleared up in connexion with 
the life-history and anatomy of this interesting parasite. It 
would be an easy and pleasant problem for any botanist who 
found himself in Chili with sufficient leisure for the purpose. 
I have only to add that I am indebted to Lady Thiselton- 
Dyer for the excellent and accurate drawings of the naked-eye 
anatomy, and to Mr. Boodle for those of the microscopic 
details. 
EXPLANATION OF FIGURES IN PLATE XL. 
Illustrating Sir W. T. Thiselton-Dyer’s Morphological Notes. IV. 
Fig. 1. Portion of the external surface of a stem of Cereus Quisco , showing the 
aerial shoots of Loranthus aphyllus . It is possible that this may have been 
represented upside down. 
Fig. 2. Fibro-vascular cylinder of Cereus Quisco from which the cortical tissues 
have been dissected away leaving the haustorium (thalloid body) of Loranthus 
aphyllus in situ. 
Fig. 3. Photograph of a transverse section of one of the smaller branches of the 
thalloid body. a. and c., two zones of sclerotic periderm ; b. zone of thin-walled 
suberized periderm. The periderm of the Cereus encloses brown disorganized 
tissues, x 40. 
Fig. 4. A piece of periderm from a similar section. The outer walls ( e . w.) 
formed the external surface of the specimen, r. w., crumpled radial walls, x 180. 
Fig* 5 - Section close to the tip of a branch, p., periderm ; b. t., brown crushed 
tissue ; c. t., central pale crushed tissue ; v. b., a vascular bundle cut longitudinally ; 
a., a vascular bundle cut transversely, x 45. 
Fig. 6. Enlarged drawing of the vascular bundle a. in Fig. 5. ph. } probably 
phloem-elements; c. t., crushed tissue surrounding the bundle, x 390. 
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