Angiosp : Dicot : Polypet : Thalamifl : IVIalvales. V. 



MALVALES include a large section with general Cistifloral characters 

 combined with minor points of higher-grade specialization, remarkably constant, 

 which may be checked with comparative facility, hence affording convenient clues 

 to classification : cf. ' valvate ' sepals, a ' column ' type of androecium, nectary-glands 

 on sepals, and often 'monothecic' anthers (two-locular). Three great alliances have 

 been given family status : — 



I. The ^Malvaceae as the key group, with elaborated floral mechanism, including 

 the full set of characters previously mentioned. 



II. The Tiliaceae, a tree family, in which the flowers present simple reduction 

 variants, which may approximate the more generalized Cistifloral stock. 



III. The Sterculiaceae, in which the widest range obtains from high-grade 

 pollination mechanisms to most reduced (fly-pollinated) limiting expressions. 



In N. Temp, regions the series has been approached from the standpoint of 

 Malva and Tth'a of N. PJurope. In the Tropics all 3 families attain considerable 

 importance, not only in floral organization, but as giving fine timber-trees of forest- 

 formation, as well as economic products, textiles, fruit. 



I. Malvaceae (3 3/900), typically with pentamerous petaloid flowers, actino- 

 morphic, with ' epicalyx ' of bracteoles, convolute corolla, column-like androecium, 

 connected with the corolla and shed in one piece, as the complex prolongation of 

 a festooned androecial tract, with monothecic " anthers ' producing large spinous 

 pollen-grains. Carpels in one cycle ; few, large and multiovulate, or many with 

 I ovule each. Fruit a capsule, dehiscent, or no longer so, or as indehiscent i -seeded 

 ' cocci ', separated from the floral receptacle. 



Cf. Althaea rosea, Hollyhock, herbaceous perennial, for fine flowers, 3-4 in. 

 diam. ; epicalyx 6-lobed, anthers 240-400, monothecic, in antipetalous crests of 

 double pairs, on a column 20 mm. high ; carpels 40-50, each i ovule : fruit separat- 

 ing dry flat cocci, 8 mm. Malva svlvisln's, reduced indig. form, anthers to 80, 

 carpels to 15. 



Gossypium herbaceum. Cotton-plant of Old World. Cult, in annual rota- 

 tion. Leaves palmate, flowers yellow with purple spot at base, continued in leafy 

 lateral monochasia ; epicalyx of 3 laciniate segments ; typical column-androecium with 

 clustered anthers ; carpels 3, ovary syncarpous with many ovules in each loc. ; style 

 with 3 stigmaiic branches. Mechanism protandrous. Fruit a small capsule (20 mm.) 

 dehiscing by 3 valves ; seeds packed with hairs (cotton) of testa : endosperm with 

 fatty oil, small embryo ; cf. G. arboreum, Trop. Africa, a woody shrub : G. I'arbade7isi\ 

 Trop. Amer., seeds with ' long-staple ' hairs. Hibiscus sp. cult., epical)-x of numerous 

 segments. 



Thespesia populnea; evergreen tree of littoral forest in Tropics, also planted; 

 foliage like Poplar, flowers like Gossypium, but epicalyx reduced ; carpels 5. stigmas 

 fused in club-shaped mass. Capsule with silky seeds. 



II. Bombaceae (20/140), often separated from Malvaceae by lack of some 

 characters (no spinous pollen), and greater range in others (column-system more 

 complex), seeds with little endosperm but large embryos. 



Bombax malabaricum, Simal, Silk-Cotton Tree, Huge tree of alluvial 

 ground, to 130 ft., buttressed trunk, soft wood, conical stem-prickles, large digitately 

 5-7 lobed leaves, deciduous in hot season. Flowers (Feb.) before the leaves, large, 

 scarlet, massive, gaudy, bee- and bird-pollinated, 4-6 in. Calyx leathery, splitting 

 irregularly, with nectarv-hairs of type. Androecium in 5 outer bundles of a dozen or 

 more stout filaments 55 mm., with twisted monothecic anthers, a few intermediate 

 single filaments, and 5 inner (antisep.) branches each 2-fid with 2 anthers only : 

 no definite ' column '. Gynoecium 5-locular, with numerous ovules, style 5-lobed. 

 Fruit a large capsule, 5-6 in.; seeds packed in dense mass of brownish silky hairs 

 growing from the lining of the wall. Cotyledons much folded. 



15 



