Flora of Tropical East Africa - Lythraceae (1994)

B. Verdcourt

• Publisher: CRC Press
• Year: 2020
• ISBN:
  9781000162455
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Horticulture
• Index: Biological Sciences

This book is a comprehensive review of the genera of Lythraceae, a flowering plant family of mostly trees and shrubs, found in tropical East Africa. It presents information on their character, occurrence, habitat, phenotypic variations and distribution of each of the species under these genera.

FLORA OF TROPICAL EAST AFRICA
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LYTHRACEAE

B. VERDCOURT

Annual or perennial herbs, subshrubs, shrubs or trees. Leaves simple, opposite or verticillate, rarely alternate; stipules absent or minute. Flowers regular or slightly irregular, hermaphrodite, (3–)4, 6, 8(–16)-merous, solitary to paniculate, sometimes di- or tri-morphic. Sepals united into a tube (hypanthium), lobes valvate, often with small appendages between. Petals free, inserted towards the top of the calyx-tube, alternating with the sepals, folded in bud, or absent. Stamens usually 4 or 8, less often many (10–200) or fewer (1–2), inserted below the petals; filaments sometimes of different lengths in the different forms of flower, usually inflexed in bud; anthers 2-thecous, opening lengthwise. Ovary superior (except Punica), sessile or shortly stipitate, completely or incompletely 2–6-locular, rarely unilocular or multilocular (Punica); style simple, sometimes of different lengths in different forms of flower; stigma often ± capitate; ovules 2-numerous on axile placentas sometimes not reaching apex of ovary (parietal in one Ammannia). Fruit capsular or baccate, opening by a transverse slit or valves or bursting irregularly or ± indehiscent. Seeds numerous, without endosperm.

A family of 26 genera and 580 species. Koehne revised the family in E.P. IV. 216(1903) but I have not followed his order of genera which appears to me unnatural; Ammannia and Nesaea are clearly extremely close yet he separates them by 12 genera and places them in different tribes on highly technical characters. S. Graham et al. U.L.S. Bot. 113: 1–33 (1993)) discuss the classification of the family from a cladistic point of view and confirm the unsatisfactory character of the existing classification. Eight genera occur naturally in the Flora area and a number are also cultivated as ornamentals, one occurring also as an escape. Two species of Lagerstroemia have been cultivated.

L. speci osa (L) Pers. (L. flos-reginae Retz.) (queen of flowers, pride of India) (T.T.C.L.: 294 (1949), U.O.P.Z.: 322 (1949), Dale, Introd. Trees Uganda: 47 (1953); Jex-Blake, Gard. E. Mr., ed. 4: 117 (1957)). Tree 7–18 m. tall with much-branched rounded crown; leaves subopposite, oblong or oblong-lanceolate, up to 30 cm. long, 9 cm. wide; flowers large, mauve or pink, 5–7.5 cm. in diameter, in large elongate terminal panicles; calyx conspicuously ribbed, rusty or grey-velvety; petals 3.2–3.5 2.1–2.5 cm., with claw 5–6 mm. long; capsule 1.7–2 cm. long. Specimens have been seen as follows: Kenya, Nairobi Arboretum, 21 Apr. 1953, Williams Sangai 524; Tanzania, Lushoto District, Amani Arboretum, 4 Feb. 1971, Furuya 229 and Amani, Kiumba, 18 Mar. 1931, Greenway 2837; Uzaramo District, Dar es Salaam Botanic Garden, Jan. 1974, Ruffo 1493 and 30 Oct. 1979, Ruffo 1261; also reported from Uganda, Entebbe, also Zanzibar and Pemba and doubtless extensively grown throughout warmer wetter areas.

L. indica L. (crape myrtle, Indian lilac and sometimes wrongly pride of India) (U.O.P.Z.: 322 (1949), Dale, Introd. Trees Uganda: 47 (1953), Jex-Blake, Gard. E. Mr., ed. 4: 117 (1953)). Shrub 2–3(–6) m. tall; leaves elliptic or obovate, 1–7.5 cm. long, 0.5–3.5(–4.5) cm. wide, obtuse; flowers white, rose-pink, lilac, magenta or mauve in larger terminal panicles; calyx not ribbed; petals 1.6–2.5 × 1.4–1.6 cm., with claw 0.8–1.1 cm. long; capsule 1–1.2 cm. long. Specimens have been seen as follows: Tanzania, Lushoto, 30 Jan. 1971, Ruffo 355,20 Feb. 1971, Shabani 667 and 30 Jan. 1981, Mtui 43; Morogoro, Nov. 1955, Semsei 2393; also grown in Uganda, Kenya and Zanzibar. Masinde reports that the following specimens from Kenya are at EA — Nairobi Arboretum, 20 Mar. 1974, Mwangangi 13; Nairobi, Chiromo campus, ICIPE House, 22 Mar. 1983, Mwangangi 2446; Nairobi City Park, 24 July 1976, Kahurananga &Kiïlu 2985; Kwale District, Diani Beach, Starzenski in E.A.H.10116; he also kindly drew my attention to the existence of a hybrid between these two species of Lagerstroemia known as Likoni Hybrid raised by B.L. Perkins in Mombasa, produced by crossing a white-flowered form of L. indien (Perkins in E.A.H. 16283) as female with a blue-flowered form of L. speciosa brought from India, Kerala (Perkins in E.A.H. 16282) as male; material is preserved as Perkins in E.A H. 16284. Several species of Cuphea are grown and since one apparently has become naturalised they are dealt with in the main text.

Punica granatum L. (pomegranate) (T.T.C.L.: 464 (1949), U.O.P.Z.: 427 (illustr. on 428) (1949), Dale, Introd. Trees Uganda: 62 (1953), Jex-Blake, Gard. E. Mr., ed. 4: 124, 305 (1957)), a native of Iran and NW. India frequently put in Punicaceae (but scarcely differing from Lythraceae in its inferior ovary, the calyx-tube adnate to the ovary which is many-loculed with the locules superposed in two series, the lower with axile, the upper with parietal placentation) is widely grown for its edible fruit. Large shrub or small tree, the branches sometimes spiny; leaves opposite, subopposite or fascicled, oblong to lanceolate or obovate, up to 7.5 cm. long, glabrous; flowers orange-red or crimson, showy, ± 2.5 cm. wide; calyx urceolate-funnel-shaped; fruit 3.5–12.5 cm. in diameter, but usually about the size of an orange; seeds numerous, covered with pulp. There are numerous varieties (see Bailey, Stand. Cycl. Hort. 3: 2750 (1939)). Specimens have been seen from Kenya, Mt. Elgon, at 1815 m., Dec. 1930, Lugard 300 (apparently away from cultivations); Tanzania, Mwanza District, Igokero, Mbelo, 9 Sept. 1952, Tanner 970; Lushoto District, Mangaribi, 21 Apr. 1971, Mslzana 165 and Kitivo N. For. Res., 27 Mar. 1971, Shabani 678; Rufiji District, Mafia I., Chole I., 19 Sept. 1937, Greenway 5275. It is widely cultivated in Kenya and Dale reports it as not uncommon in Uganda; it is grown in Zanzibar and Pemba. There are attractive double-flowered forms and a dwarf variety.

Sonneratia sometimes included in the Lythraceae has already been dealt with as a separate family.

1. Trees or shrubs	2
Herbs or subshrubs, mostly under 1 m. tall (except the woody perennial Cup hea mieropetala)	6
2. Ovary inferior; fruit large, 3.5–12.5 cm. in diameter, the seeds covered in juicy pulp; flowers large, bright red	Punica (see above)
Ovary superior; fruit smaller	3
3. Leaves black-dotted; flowers somewhat zygomorphic in axillary cymes; calyx-tube tubular, longer than broad	1. Woodfordia
Leaves not black-dotted, flowers regular in terminal panicles or solitary (rarely paired) in the leaf-axils; calyx-tube broader than long	4
4. Stamens numerous; petals 6; capsule not enclosed within calyx-tube; cultivated trees and shrubs with showy flowers having clawed petals	Lagerstroenda (see above)
Stamens 4,8, 12 or 18; petals 4 or 6; capsule enclosed or not in calyx-tube; indigenous plants with small flowers	5
5. Flowers solitary or rarely paired in leaf-axils; petals 6; fruit enclosed by or just exserted from calyx, ± 1-locular, circumscissile; silky pubescent littoral shrub of mangrove swamp edges, dunes, etc	3. Pemphis
Flowers in dense terminal panicles; petals 4; fruit sitting on ± peltate calyx, 2–4-locular, indehiscent or bursting irregularly; glabrous shrub not confined to littoral areas	4. Lawsonia
6. Calyx-tube usually ± curved, over 1 cm. long, gibbous at the base, oblique at the throat; cultivated and one naturalised	2. Cuphea
Calyx-tube symmetrical, up to 5 mm. long; indigenous	7
7. Capsule opening by well-defined minutely transversely striate valves; ovary not divided into locules to apex, the placenta not continuous with the style	9. Rotala
Capsule ± circumscissile or bursting irregularly or if opening by valves then not transversely striate; ovary completely or incompletely divided into locules	8
8. Flowers solitary; calyx tubul...

Table of contents

• Cover
• Title Page
• Copyright Page
• Lythraceae
• Index to Lythraceae