386 



NATURAL HISTORY OF PLANTS. 



has a pentamerous calyx, corolla, and androceum inserted on the rim 

 of a concave receptacle ; this is often warty outside, and lodges in its 

 concavity more or less of the two-celled ovary, which has from two 

 to four descending ovules in each cell. But the septum being in 

 great part absorbed, there is left an apparently free central placentary 

 column, bearing near its apex 1 a crown of ovules. 2 A simple style 

 surmounts the ovary. Four species of Thamnea proper have been 

 described, 3 little shrubs or undershrubs from the Cape, with minute 

 imbricate leaves and solitary flowers terminating the branches or 

 short axillary twigs. 



Brirnia laxa? which has been made the type of a genus Tittmannia," 

 is a somewhat exceptional Thamnea, its flowers being directly axillary 

 to the leaves, and the septum 6 between its two biovulate cells being 

 destroyed less rapidly and completely 7 than in Thamnea proper; 

 accordingly, this genus may be regarded as forming the type of a 

 distinct section of the genus. 



XVI. HAMAMELIS SERIES. 



The flowers of Hamamelitf (figs. 462-464) are hermaphrodite or 

 polygamous. In the former case the receptacle forms a deep cup, 

 with four sepals of alternative-imbricate aestivation inserted on its 

 rim. Between these are four long riband-shaped petals, involute in 

 the bud. There are eight stamens in two whorls, four being super- 

 posed to the sepals and four to the petals. The former alone are 



1 This differs from truly free central placentas 

 in that its enlarged apex adheres to the roof of 

 the ovary. 



2 Descending, as in the other Bruniece, and, 

 as it appeared to us, with the inicropyle finally 

 upwards and outwards in the expanded flower. 



3 Haey. & Sond., Fl. Cap., ii. 324— OltlV., 

 loo. cit., 331, 332. 



4 Thttnb., Fl. Cap., 206.— Mcesslera late- 

 riflora Reichb., Consp., 160. — Eckl. & Zeyh., 

 Fnum., 1086. 



5 Ad. Be., loc. cit., 29, t. 4, fig. 2. — Endl., 

 Gen., n. 4603.— Haet. & Sond., Fl. Cap , ii 

 312.— B. H., Gen., 671, n. 3. 



6 The presence of this septum leads Oliteb 

 (loc. cit., 333) to include our Thamnea laxa in 

 the genus Brunia. 



' However, we have found numerous flowers 

 where the placenta was finally quite as free as in 

 the other flowers. Hence this character is in- 

 sufficient to separate the two types, and so is the 

 difference of insertion of the flowers (axillary or 

 terminal), which appears of no importance when 

 we find flowers of Thamnea proper ending ex- 

 tremely short axillary twigs. 



8 L., Gen., n. 169. — J., Gen., 288.— Lame., 

 Bid., iii. 68; III,, t. 88.— DC, Prodr., iv. 268 

 (part.). — Enbl., Gen., n. 4591. — Ag., Theor. 

 Syst., t. 13. — H. Bn., in Adansonia, iii. 323; v. 

 298; x. fasc. 4; in Payer Fam. Nat., 345. — 

 B. H., Gen., 667, n. 7. — Trilopus Mich., in Ann. 

 Nat. Cur., viii. (ex Aixans., Fam. des PI., ii. 

 381). 



