908 cv. PODOSTEMACE^. [Tristicha 



with red or purple, in the dry state dull reddish ; leaves broader and 

 more densely trifariously imbricate than those of the last species,- dull 

 or almost obscurely green without gloss, those of the third row erect, 

 adpressed to the stem more or less orbicular and half the length of 

 those in the distichously spreading other rows ; capsules almost equal in 

 size to those of the last species ; the whole plant turning black in 

 drying. Attached to submerged rocks in the stream Casalale' in the 

 presidium, rather rarely flowering ; fl. and fr. Feb. 1857. No. 528. 

 By the rivers Casalale and Cambondo ; fl. and fr. Jan. 1857. CoLi.. 

 Carp. 942. It flowers from January to March. Several species of 

 Algae grew on the branches. Cf. Algae nn. 105, 108, 109. 



CVI. CYTINACE^. 



1. PILOSTYLES Guillemin in Ann. Sc. Nat., ser. 2, ii. p. 19. 

 t. 1 (1834). 



Frostia Bertero ex Guillemin, I.e. Apodmithes Benth. & Hook, 

 f. Gen. PI. iii. p. 118; non Poit. (1824). 



1. P. aethiopica Welw. in Trans. Linn. Soc. xxvii. p. 67. t. 22 

 (1869); Hook. f. in DC. Prodr. xvii. p. 114 (1873). 



A small parasite, growing in masses, after the fashion of the 

 tubercle-shaped Sphterije, on the thinner branchlets of trees on all 

 sides, but chiefly on the side exposed to the light, springing from 

 their bark sometimes in definite rows and in other cases irregularly. 

 Slender threads or very delicate membranes pervade the liber and 

 take the place of the root like a mycelium. The parasites first 

 appear as small hemispherical nodules, which are afterwards 

 broken by the protrusion of a rather hard globular or somewhat 

 conical light brown body appearing under the microscope to be 

 covered with small tender more or less circular scales which give 

 the globular body an areolate surface and make it quite analogous 

 to the uterus of some Fungi, as for instance Clathrus, and almost 

 of a woody consistency ; it soon bursts either irregularly or in a 

 circumsciss manner, the upper arched part falling o& like a hood, 

 and the lower part remaining firm on the bark like an elevated 

 bowl-shaped ring, which permanently encircles the buds as they 

 sprout and the fruit when subsequently formed. The whole of 

 the process, from the first manifestation of the little nodules up 

 to the inflorescence and fructification, appears to be completed in 

 a very few days: thus Welwitsch found on the 10th May 1860 

 male flowers which were then nearly all in bud with only a few 

 having their perianth expanded, and two days later he found the 

 same flowers nearly all quite wdthered and past. On a close 

 examination of these fungus like plants Welwitsch was involun- 

 tarily reminded of the flowers of certain Asclepiadeaj especially 

 of some Stajjelice ; and the foul smell of the latter is said to occur 

 in some species of Rafllesieae. The flowers are dioecious, involu- 

 crate ; involucre globose, crustaceous, pale brown, branny-areolate, 

 smooth inside, enclosing one or rarely two (in one instance three) 

 flowers, circumsciss or bursting irregularly, the patelliform base 



